Quantum anti-Zeno effect in artificial quantum systems

In this paper, we study a quantum anti-Zeno effect (QAZE) purely induced by repetitive measurements for an artificial atom interacting with a structured bath. This bath can be artificially realized with coupled resonators in one dimension and possesses photonic band structure like Bloch electron in a periodic potential. In the presence of repetitive measurements, the pure QAZE is discovered as the observable decay is not negligible even for the atomic energy level spacing outside of the energy band of the artificial bath. If there were no measurements, the decay would not happen outside of the band. In this sense, the enhanced decay is completely induced by measurements through the relaxation channels provided by the bath. Besides, we also discuss the controversial golden rule decay rates originated from the van Hove's singularities and the effects of the counter-rotating terms.Comment: 12 pages, 8 figure

Aspisol inhibits tumor growth and induces apoptosis in breast cancer

Nonsteroidal anti-inflammatory drugs inhibit cell proliferation and induce apoptosis in various cancer cell lines, which is considered to be an important mechanism for their anti-tumor activity and cancer prevention. However, the molecular mechanisms through which these compounds induce apoptosis are not well understood. Aim: to determine the effects of nonselective cyclooxygenase-2 (COX-2) inhibitor, aspisol on breast cancer cells in vitro and in vivo. Methods: The cytotoxic activity of aspisol was evaluated by MTT assay. The apoptosis index of cells was measured by flow cytometry. Immunohistochemical staining was used to detect expressions of COX-2 and caspase-3 in MDA-MB-231 cells. The expression of bcl-2 and bax was analyzed by Western blot analysis. The content of prostaglandin E2 (PGE2) in MDA-MB-231 cells was estimated by ELISA. In vivo apoptosis of the tumor cells was detected by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL). Results: Our results showed that aspisol reduced viability of MDA-MB-231 cells in time- and dose- dependent fashions and induced apoptosis by increase of caspase-3 and bax expressions while decrease of COX-2 and bcl-2 expression in vitro. In addition, exposure to aspisol decreased the basal release of PGE2. In vivo, aspisol also inhibited the proliferation of breast cancer cells and induced their apoptosis. Conclusions: Our in vitro and in vivo data indicated that the antitumor effects of aspisol on breast cancer cells was probably mediated by the induction of apoptosis, and it could be linked to the downregulation of the COX-2 or bcl-2 expression and up-regulation of caspase-3 or bax expression.Нестероидные противовоспалительные препараты ингибируют пролиферацию клеток и вызывают апоптоз во многих опухолевых клеточных линиях, что считается важным механизмом их противоопухолевой активности и профилактики развития рака. Тем не менее молекулярные механизмы апоптотического действия этих препаратов изучены недостаточно. Цель: изучить действие неспецифического ингибитора циклогексиназы-2 (COX-2) — аспизола — на злокачественные клетки рака молочной железы in vitro и in vivo. Методы: выживаемоть клеток MDA-MB-231 определяли с помощью MTT-теста. Апоптотический индекс измеряли с помощью проточной цитометрии и иммуногистохимическим окрашиванием с антителами против COX-2 и каспазы-3. Экспрессию bcl-2 и bax изучали с помощью Вестерн-блот-анализа. Содержание простагландина E2 (PGE2 ) в клетках MDA-MB-231 оценивали методом ELISA. In vivo апоптоз опухолевых клеток определяли путем выявления разрывов ДНК с помощью концевой дезоксинуклеот-идилтранферазы (метод TUNEL). Результаты: показано, что в зависимости от времени инкубации и дозы аспизол угнетал рост клеток MDA-MB-231 in vitro и вызывал их апоптоз на фоне повышения экспрессии каспазы-3 и bax, а также снижения экспрессии COX-2 и bcl-2. В условиях in vivo аспизол также ингибировал пролиферацию злокачественных клеток рака молочной железы и вызывал их апоптоз. Выводы: данные, полученные in vitro и in vivo, свидетельствуют о противоопухолевом эффекте аспизола на клетки рака молочной железы, что скорее всего опосредовано его проапоптотическим действием и может быть связано со снижением экспрессии COX-2 и bcl-2, а также повышением экспрессии каспазы-3 и bax

Dynamics of quantum entanglement in the reservoir with memory effects

The non-Markovian dynamics of quantum entanglement is studied by the Shabani-Lidar master equation when one of entangled quantum systems is coupled to a local reservoir with memory effects. The completely positive reduced dynamical map can be constructed in the Kraus representation. Quantum entanglement decays more slowly in the non-Markovian environment. The decoherence time for quantum entanglement can be markedly increased by the change of the memory kernel. It is found out that the entanglement sudden death between quantum systems and entanglement sudden birth between the system and reservoir occur at different instants.Comment: 14 pages, 3 figure

Candidates for membrane progestin receptors: past approaches and future challenges

Progestins have a broad range of functions in reproductive biology. Many rapid nongenomic actions of progestins have been identified, including induction of oocyte maturation, modulation of reproductive signaling in the brain, rapid activation of breast cancer cell signaling, induction of the acrosomal reaction and hypermotility in mammalian sperm. Currently, there are three receptor candidates for mediating rapid progestin actions: (1) membrane progestin receptors (mPRs); (2) progestin receptor membrane components (PGRMCs); and (3) nuclear progestin receptors (nPRs). The recently-described mPR family of proteins has seven integral transmembrane domains and mediates signaling via G-protein coupled pathways. The PGRMCs have a single transmembrane with putative Src homology domains for potential activation of second messengers. The classical nPRs, in addition to having well defined transcriptional activity, can also mediate rapid activation of intracellular signaling pathways. However, details of the mechanisms by which these three classes of progestin receptors mediate rapid intracellular signaling and their subcellular localization remain unclear. In addition, mPRs, nPRs and PGRMCs exhibit overlapping expression and functions in multiple tissues, implying potential interactions during oocyte maturation, parturition, and breast cancer signaling in individual cells. However, the overwhelming majority of studies to date have focused on the functions of one of these groups of receptors in isolation. This review will summarize recent findings on the three major progestin receptor candidates, emphasizing the different approaches used, some experimental pitfalls, and current controversies. We will also review evidence for the involvement of mPRs and nPRs in one of the most well-characterized nongenomic steroid actions in basal vertebrates, oocyte maturation, and conclude by suggesting some future areas of research. Clarification of the controversies surrounding the identities and localization of membrane progestin receptors may help direct future research that could advance our understanding of rapid actions of steroids.Animal science

Hadronic Parity Violation and Inelastic Electron-Deuteron Scattering

We compute contributions to the parity-violating (PV) inelastic electron-deuteron scattering asymmetry arising from hadronic PV. While hadronic PV effects can be relatively important in PV threshold electro- disintegration, we find that they are highly suppressed at quasielastic kinematics. The interpretation of the PV quasielastic asymmetry is, thus, largely unaffected by hadronic PV.Comment: 27 pages, 13 figures, uses REVTeX and BibTe

Search for the Rare Decays J/Psi --> Ds- e+ nu_e, J/Psi --> D- e+ nu_e, and J/Psi --> D0bar e+ e-

We report on a search for the decays J/Psi --> Ds- e+ nu_e + c.c., J/Psi --> D- e+ nu_e + c.c., and J/Psi --> D0bar e+ e- + c.c. in a sample of 5.8 * 10^7 J/Psi events collected with the BESII detector at the BEPC. No excess of signal above background is observed, and 90% confidence level upper limits on the branching fractions are set: B(J/Psi --> Ds- e+ nu_e + c.c.)<4.8*10^-5, B(J/Psi --> D- e+ nu_e + c.c.) D0bar e+ e- + c.c.)<1.1*10^-5Comment: 10 pages, 4 figure

Pulsar Timing and its Application for Navigation and Gravitational Wave Detection

Pulsars are natural cosmic clocks. On long timescales they rival the precision of terrestrial atomic clocks. Using a technique called pulsar timing, the exact measurement of pulse arrival times allows a number of applications, ranging from testing theories of gravity to detecting gravitational waves. Also an external reference system suitable for autonomous space navigation can be defined by pulsars, using them as natural navigation beacons, not unlike the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location (e.g. the solar system barycenter), the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. We describe the unique properties of pulsars that suggest that such a navigation system will certainly have its application in future astronautics. We also describe the on-going experiments to use the clock-like nature of pulsars to "construct" a galactic-sized gravitational wave detector for low-frequency (f_GW ~1E-9 - 1E-7 Hz) gravitational waves. We present the current status and provide an outlook for the future.Comment: 30 pages, 9 figures. To appear in Vol 63: High Performance Clocks, Springer Space Science Review

Study of J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar

The branching ratios and Angular distributions for J/psi decays to Lambda Lambdabar and Sigma0 Sigma0bar are measured using BESII 58 million J/psi.Comment: 11 pages, 5 figure

Direct Measurements of the Branching Fractions for D0→K−e+νeD^0 \to K^-e^+\nu_e and D0→π−e+νeD^0 \to \pi^-e^+\nu_e and Determinations of the Form Factors f+K(0)f_{+}^{K}(0) and f+π(0)f^{\pi}_{+}(0)

The absolute branching fractions for the decays $D^0 \to K^-e ^+\nu_e$ and $D^0 \to \pi^-e^+\nu_e$ are determined using $7584\pm 198 \pm 341$ singly tagged $\bar D^0$ sample from the data collected around 3.773 GeV with the BES-II detector at the BEPC. In the system recoiling against the singly tagged $\bar D^0$ meson, $104.0\pm 10.9$ events for $D^0 \to K^-e ^+\nu_e$ and $9.0 \pm 3.6$ events for $D^0 \to \pi^-e^+\nu_e$ decays are observed. Those yield the absolute branching fractions to be $BF(D^0 \to K^-e^+\nu_e)=(3.82 \pm 0.40\pm 0.27)$ and $BF(D^0 \to \pi^-e^+\nu_e)=(0.33 \pm 0.13\pm 0.03)$. The vector form factors are determined to be $|f^K_+(0)| = 0.78 \pm 0.04 \pm 0.03$ and $|f^{\pi}_+(0)| = 0.73 \pm 0.14 \pm 0.06$. The ratio of the two form factors is measured to be $|f^{\pi}_+(0)/f^K_+(0)|= 0.93 \pm 0.19 \pm 0.07$.Comment: 6 pages, 5 figure