966 research outputs found
Transport of charged particles by adjusting rf voltage amplitudes
We propose a planar architecture for scalable quantum information processing
(QIP) that includes X-junctions through which particles can move without
micromotion. This is achieved by adjusting radio frequency (rf) amplitudes to
move an rf null along the legs of the junction. We provide a proof-of-principle
by transporting dust particles in three dimensions via adjustable rf potentials
in a 3D trap. For the proposed planar architecture, we use regularization
techniques to obtain amplitude settings that guarantee smooth transport through
the X-junction.Comment: 16 pages, 10 figure
Medication Assisted Treatment: Experiences from the Field
The use of heroin and other opiates has increased considerably in recent years with many users
becoming involved with the criminal justice system. Because of this growth, the use of
medication assisted treatment is becoming increasingly popular in courts that specialize in opiate
addictions. This paper analyzes the experiences of treatment teams in courts that specialize in
providing medication assisted treatment. Overall, perceptions of medication assisted treatment
were positive although service providers identified some limitations. Recognizing the benefits
and limitations of medication assisted treatment is useful for social work practice that focuses on
opiate addictions because heroin use continues to rise
High-fidelity quantum driving
The ability to accurately control a quantum system is a fundamental
requirement in many areas of modern science such as quantum information
processing and the coherent manipulation of molecular systems. It is usually
necessary to realize these quantum manipulations in the shortest possible time
in order to minimize decoherence, and with a large stability against
fluctuations of the control parameters. While optimizing a protocol for speed
leads to a natural lower bound in the form of the quantum speed limit rooted in
the Heisenberg uncertainty principle, stability against parameter variations
typically requires adiabatic following of the system. The ultimate goal in
quantum control is to prepare a desired state with 100% fidelity. Here we
experimentally implement optimal control schemes that achieve nearly perfect
fidelity for a two-level quantum system realized with Bose-Einstein condensates
in optical lattices. By suitably tailoring the time-dependence of the system's
parameters, we transform an initial quantum state into a desired final state
through a short-cut protocol reaching the maximum speed compatible with the
laws of quantum mechanics. In the opposite limit we implement the recently
proposed transitionless superadiabatic protocols, in which the system perfectly
follows the instantaneous adiabatic ground state. We demonstrate that
superadiabatic protocols are extremely robust against parameter variations,
making them useful for practical applications.Comment: 17 pages, 4 figure
A Minimal Threshold of c-di-GMP Is Essential for Fruiting Body Formation and Sporulation in Myxococcus xanthus
Generally, the second messenger bis-(3â-5â)-cyclic dimeric GMP (c-di-GMP) regulates the switch between motile and sessile lifestyles in bacteria. Here, we show that c-di-GMP is an essential regulator of multicellular development in the social bacterium Myxococcus xanthus. In response to starvation, M. xanthus initiates a developmental program that culminates in formation of spore-filled fruiting bodies. We show that c-di-GMP accumulates at elevated levels during development and that this increase is essential for completion of development whereas excess c-di-GMP does not interfere with development. MXAN3735 (renamed DmxB) is identified as a diguanylate cyclase that only functions during development and is responsible for this increased c-di-GMP accumulation. DmxB synthesis is induced in response to starvation, thereby restricting DmxB activity to development. DmxB is essential for development and functions downstream of the Dif chemosensory system to stimulate exopolysaccharide accumulation by inducing transcription of a subset of the genes encoding proteins involved in exopolysaccharide synthesis. The developmental defects in the dmxB mutant are non-cell autonomous and rescued by co-development with a strain proficient in exopolysaccharide synthesis, suggesting reduced exopolysaccharide accumulation as the causative defect in this mutant. The NtrC-like transcriptional regulator EpsI/Nla24, which is required for exopolysaccharide accumulation, is identified as a c-diGMP receptor, and thus a putative target for DmxB generated c-di-GMP. Because DmxB can beâat least partiallyâfunctionally replaced by a heterologous diguanylate cyclase, these results altogether suggest a model in which a minimum threshold level of c-di-GMP is essential for the successful completion of multicellular development in M. xanthus
Rectal Transmission of Transmitted/Founder HIV-1 Is Efficiently Prevented by Topical 1% Tenofovir in BLT Humanized Mice
Rectal microbicides are being developed to prevent new HIV infections in both men and women. We focused our in vivo preclinical efficacy study on rectally-applied tenofovir. BLT humanized mice (nâ=â43) were rectally inoculated with either the primary isolate HIV-1(JRCSF) or the MSM-derived transmitted/founder (T/F) virus HIV-1(THRO) within 30 minutes following treatment with topical 1% tenofovir or vehicle. Under our experimental conditions, in the absence of drug treatment we observed 50% and 60% rectal transmission by HIV-1(JRCSF) and HIV-1(THRO), respectively. Topical tenofovir reduced rectal transmission to 8% (1/12; log rank pâ=â0.03) for HIV-1(JRCSF) and 0% (0/6; log rank pâ=â0.02) for HIV-1(THRO). This is the first demonstration that any human T/F HIV-1 rectally infects humanized mice and that transmission of the T/F virus can be efficiently blocked by rectally applied 1% tenofovir. These results obtained in BLT mice, along with recent ex vivo, Phase 1 trial and non-human primate reports, provide a critically important step forward in the development of tenofovir-based rectal microbicides
Mandibular Actinomyces osteomyelitis complicating florid cemento-osseous dysplasia: case report
Evaluation of polygenic risk scores for breast and ovarian cancer risk prediction in BRCA1 and BRCA2 mutation carriers
Background: Genome-wide association studies (GWAS) have identified 94 common single-nucleotide polymorphisms (SNPs) associated with breast cancer (BC) risk and 18 associated with ovarian cancer (OC) risk. Several of these are also associated with risk of BC or OC for women who carry a pathogenic mutation in the high-risk BC and OC genes BRCA1 or BRCA2. The combined effects of these variants on BC or OC risk for BRCA1 and BRCA2 mutation carriers have not yet been assessed while their clinical management could benefit from improved personalized risk estimates.
Methods: We constructed polygenic risk scores (PRS) using BC and OC susceptibility SNPs identified through population-based GWAS: for BC (overall, estrogen receptor [ER]-positive, and ER-negative) and for OC. Using data from 15 252 female BRCA1 and 8211 BRCA2 carriers, the association of each PRS with BC or OC risk was evaluated using a weighted cohort approach, with time to diagnosis as the outcome and estimation of the hazard ratios (HRs) per standard deviation increase in the PRS.
Results: The PRS for ER-negative BC displayed the strongest association with BC risk in BRCA1 carriers (HR = 1.27, 95% confidence interval [CI] = 1.23 to 1.31, P = 8.2 x 10(53)). In BRCA2 carriers, the strongest association with BC risk was seen for the overall BC PRS (HR = 1.22, 95% CI = 1.17 to 1.28, P = 7.2 x 10(-20)). The OC PRS was strongly associated with OC risk for both BRCA1 and BRCA2 carriers. These translate to differences in absolute risks (more than 10% in each case) between the top and bottom deciles of the PRS distribution; for example, the OC risk was 6% by age 80 years for BRCA2 carriers at the 10th percentile of the OC PRS compared with 19% risk for those at the 90th percentile of PRS.
Conclusions: BC and OC PRS are predictive of cancer risk in BRCA1 and BRCA2 carriers. Incorporation of the PRS into risk prediction models has promise to better inform decisions on cancer risk management
BRCA2 polymorphic stop codon K3326X and the risk of breast, prostate, and ovarian cancers
Background: The K3326X variant in BRCA2 (BRCA2*c.9976A>T; p.Lys3326*; rs11571833) has been found to be associated with small increased risks of breast cancer. However, it is not clear to what extent linkage disequilibrium with fully pathogenic mutations might account for this association. There is scant information about the effect of K3326X in other hormone-related cancers.
Methods: Using weighted logistic regression, we analyzed data from the large iCOGS study including 76 637 cancer case patients and 83 796 control patients to estimate odds ratios (ORw) and 95% confidence intervals (CIs) for K3326X variant carriers in relation to breast, ovarian, and prostate cancer risks, with weights defined as probability of not having a pathogenic BRCA2 variant. Using Cox proportional hazards modeling, we also examined the associations of K3326X with breast and ovarian cancer risks among 7183 BRCA1 variant carriers. All statistical tests were two-sided.
Results: The K3326X variant was associated with breast (ORw = 1.28, 95% CI = 1.17 to 1.40, P = 5.9x10- 6) and invasive ovarian cancer (ORw = 1.26, 95% CI = 1.10 to 1.43, P = 3.8x10-3). These associations were stronger for serous ovarian cancer and for estrogen receptorânegative breast cancer (ORw = 1.46, 95% CI = 1.2 to 1.70, P = 3.4x10-5 and ORw = 1.50, 95% CI = 1.28 to 1.76, P = 4.1x10-5, respectively). For BRCA1 mutation carriers, there was a statistically significant inverse association of the K3326X variant with risk of ovarian cancer (HR = 0.43, 95% CI = 0.22 to 0.84, P = .013) but no association with breast cancer. No association with prostate cancer was observed.
Conclusions: Our study provides evidence that the K3326X variant is associated with risk of developing breast and ovarian cancers independent of other pathogenic variants in BRCA2. Further studies are needed to determine the biological mechanism of action responsible for these associations
Two photon decays of heavy vector mesons, ,, and the possible determination of the and couplings
We study the novel decays and using the framework of the Heavy Meson Chiral Lagrangian (HML)
to leading order in chiral perturbation theory. The branching ratios of these
decays are expressed in terms of the strong and the
electromagnetic couplings, thus providing a possible
tool for their determination. In the charm case, using the experimentally
determined ratios we are able
to express the branching ratio as a function of the strong coupling only. We
thus find for where is the strong
coupling of HML. In the beauty sector, the which we estimate to be in the range is a
function of both and Its behaviour does not
afford an unambiguous determination of these couplings except for the region of
high values like The expected two-photon differential
distributions are presented for both and
for different values of the couplings
involved.Comment: 22 pages, LaTeX, 5 ps-figures (uses subfigure.sty). Accepted by Phys.
Rev.
- âŚ