97 research outputs found
Segmented Composite Design of Robust Single-Qubit Quantum Gates
Error mitigation schemes and error-correcting codes have been the center of
much effort in quantum information processing research over the last few
decades. While most of the successful proposed schemes for error mitigation are
perturbative in the noise and assume deterministic systematic errors, studies
of the problem considering the full noise and errors distribution are still
scarce. In this work, we introduce an error mitigation scheme for robust
single-qubit unitary gates based on composite segmented design, which accounts
for the full distribution of the physical noise and errors in the system. We
provide two optimization approaches to construct these robust segmented gates:
perturbative and non-perturbative, that addresses all orders of errors. We
demonstrate our scheme in the photonics realm for the dual-rail directional
couplers realization. We show that the 3-segmented composite design for the
fundamental single-qubits unitary operations reduces the error by an order of
magnitude for a realistic distribution of errors, and that the two approaches
are compatible for small errors. This is shown to significantly reduce the
overhead of modern error correction codes. Our methods are rather general and
can be applied to other realizations of quantum information processing units
A Novel Translocation Breakpoint within the BPTF Gene Is Associated with a Pre-Malignant Phenotype
Partial gain of chromosome arm 17q is an abundant aberrancy in various cancer types such as lung and prostate cancer with a prominent occurrence and prognostic significance in neuroblastoma – one of the most common embryonic tumors. The specific genetic element/s in 17q responsible for the cancer-promoting effect of these aberrancies is yet to be defined although many genes located in 17q have been proposed to play a role in malignancy. We report here the characterization of a naturally-occurring, non-reciprocal translocation der(X)t(X;17) in human lung embryonal-derived cells following continuous culturing. This aberrancy was strongly correlated with an increased proliferative capacity and with an acquired ability to form colonies in vitro. The breakpoint region was mapped by fluorescence in situ hybridization (FISH) to the 17q24.3 locus. Further characterization by a custom-made comparative genome hybridization array (CGH) localized the breakpoint within the Bromodomain PHD finger Transcription Factor gene (BPTF), a gene involved in transcriptional regulation and chromatin remodeling. Interestingly, this translocation led to elevation in the mRNA levels of the endogenous BPTF. Knock-down of BPTF restricted proliferation suggesting a role for BPTF in promoting cellular growth. Furthermore, the BPTF chromosomal region was found to be amplified in various human tumors, especially in neuroblastomas and lung cancers in which 55% and 27% of the samples showed gain of 17q24.3, respectively. Additionally, 42% percent of the cancer cell lines comprising the NCI-60 had an abnormal BPTF locus copy number. We suggest that deregulation of BPTF resulting from the translocation may confer the cells with the observed cancer-promoting phenotype and that our cellular model can serve to establish causality between 17q aberrations and carcinogenesis
Modulated expression of WFDC1 during carcinogenesis and cellular senescence
Fibroblasts located adjacent to the tumor [cancer-associated fibroblasts (CAFs)] that constitute a large proportion of the cancer-associated stroma facilitate the transformation process. In this study, we compared the biological behavior of CAFs that were isolated from a prostate tumor to their normal-associated fibroblast (NAF) counterparts. CAFs formed more colonies when seeded at low cell density, exhibited a higher proliferation rate and were less prone to contact inhibition. In contrast to the general notion that high levels of α-smooth muscle actin serve as a marker for CAFs, we found that prostate CAFs express it at a lower level compared with prostate NAFs. Microarray analysis revealed a set of 161 genes that were altered in CAFs compared with NAFs. We focused on whey acidic protein four-disulfide core domain 1 (WFDC1), a known secreted protease inhibitor, and found it to be downregulated in the CAFs. WFDC1 expression was also dramatically downregulated in highly prolific mesenchymal cells and in various cancers including fibrosarcomas and in tumors of the lung, bladder and brain. Overexpression of WFDC1 inhibited the growth rate of the fibrosarcoma HT1080 cell line. Furthermore, WFDC1 level was upregulated in senescent fibroblasts. Taken together, our data suggest an important role for WFDC1 in inhibiting proliferation of both tumors and senescent cells. Finally, we suggest that the downregulation of WFDC1 might serve as a biomarker for cellular transformation
The Zwicky Transient Facility Census of the Local Universe. I. Systematic Search for Calcium-rich Gap Transients Reveals Three Related Spectroscopic Subclasses
Using the Zwicky Transient Facility alert stream, we are conducting a large spectroscopic campaign to construct a complete, volume-limited sample of transients brighter than 20 mag, and coincident within 100" of galaxies in the Census of the Local Universe catalog. We describe the experiment design and spectroscopic completeness from the first 16 months of operations, which have classified 754 supernovae. We present results from a systematic search for calcium-rich gap transients in the sample of 22 low-luminosity (peak absolute magnitude M > −17), hydrogen-poor events found in the experiment. We report the detection of eight new events, and constrain their volumetric rate to ≳ 15% ± 5% of the SN Ia rate. Combining this sample with 10 previously known events, we find a likely continuum of spectroscopic properties ranging from events with SN Ia–like features (Ca-Ia objects) to those with SN Ib/c–like features (Ca-Ib/c objects) at peak light. Within the Ca-Ib/c events, we find two populations distinguished by their red (g − r ≈ 1.5 mag) or green (g - r ≈ 0.5 mag) colors at the r-band peak, wherein redder events show strong line blanketing features and slower light curves (similar to Ca-Ia objects), weaker He lines, and lower [Ca ii]/[O i] in the nebular phase. We find that all together the spectroscopic continuum, volumetric rates, and striking old environments are consistent with the explosive burning of He shells on low-mass white dwarfs. We suggest that Ca-Ia and red Ca-Ib/c objects arise from the double detonation of He shells, while green Ca-Ib/c objects are consistent with low-efficiency burning scenarios like detonations in low-density shells or deflagrations
TMPRSS2/ERG Promotes Epithelial to Mesenchymal Transition through the ZEB1/ZEB2 Axis in a Prostate Cancer Model
Prostate cancer is the most common non-dermatologic malignancy in men in the Western world. Recently, a frequent chromosomal aberration fusing androgen regulated TMPRSS2 promoter and the ERG gene (TMPRSS2/ERG) was discovered in prostate cancer. Several studies demonstrated cooperation between TMPRSS2/ERG and other defective pathways in cancer progression. However, the unveiling of more specific pathways in which TMPRSS2/ERG takes part, requires further investigation. Using immortalized prostate epithelial cells we were able to show that TMPRSS2/ERG over-expressing cells undergo an Epithelial to Mesenchymal Transition (EMT), manifested by acquisition of mesenchymal morphology and markers as well as migration and invasion capabilities. These findings were corroborated in vivo, where the control cells gave rise to discrete nodules while the TMPRSS2/ERG-expressing cells formed malignant tumors, which expressed EMT markers. To further investigate the general transcription scheme induced by TMPRSS2/ERG, cells were subjected to a microarray analysis that revealed a distinct EMT expression program, including up-regulation of the EMT facilitators, ZEB1 and ZEB2, and down-regulation of the epithelial marker CDH1(E-Cadherin). A chromatin immunoprecipitation assay revealed direct binding of TMPRSS2/ERG to the promoter of ZEB1 but not ZEB2. However, TMPRSS2/ERG was able to bind the promoters of the ZEB2 modulators, IL1R2 and SPINT1. This set of experiments further illuminates the mechanism by which the TMPRSS2/ERG fusion affects prostate cancer progression and might assist in targeting TMPRSS2/ERG and its downstream targets in future drug design efforts
Atomic spectrometry update: Review of advances in the analysis of metals, chemicals and materials
There has been a large increase in the number of papers published that are relevant to this review over this review period. The growth in popularity of LIBS is rapid, with applications being published for most sample types. This is undoubtedly because of its capability to analyse in situ on a production line (hence saving time and money) and its minimally destructive nature meaning that both forensic and cultural heritage samples may be analysed. It also has a standoff analysis capability meaning that hazardous materials, e.g. explosives or nuclear materials, may be analysed from a safe distance. The use of mathematical algorithms in conjunction with LIBS to enable improved accuracy has proved a popular area of research. This is especially true for ferrous and non-ferrous samples. Similarly, chemometric techniques have been used with LIBS to aid in the sorting of polymers and other materials. An increase in the number of papers in the subject area of alternative fuels was noted. This was at the expense of papers describing methods for the analysis of crude oils. For nanomaterials, previous years have seen a huge number of single particle and field flow fractionation characterisations. Although several such papers are still being published, the focus seems to be switching to applications of the nanoparticles and the mechanistic aspects of how they retain or bind with other analytes. This is the latest review covering the topic of advances in the analysis of metals, chemicals and materials. It follows on from last year's review1-6 and is part of the Atomic Spectrometry Updates series
Predictions from masked motion with and without obstacles.
Predicting the future is essential for organisms like Homo sapiens, who live in a dynamic and ever-changing world. Previous research has established that conscious stimuli can lead to non-conscious predictions. Here we examine whether masked stimuli can also induce such predictions. We use masked movement-with and without obstacles-to examine predictions from masked stimuli. In six experiments a moving object was masked using continuous flash suppression (CFS). A few hundred milliseconds after the object had disappeared, a conscious probe appeared in a location that was either consistent with the masked stimulus or not. In Experiments 1-3 the movement was linear, and reaction times (RTs) indicated predictions that were based on direction and speed of movement. In Experiment 4, the masked moving object collided with an obstacle and then disappeared. Predictions in this case should reflect deflection, and indeed reaction times revealed predictions on the deflection route. In Experiments 5 and 6 we introduce an innovative way of using eye-tracking during continuous flash suppression (CFS) and report physiological evidence-in the forms of eye-movements-for masked stimuli induced predictions. We thus conclude that humans can use dynamic masked stimuli to generate active predictions about the future, and use these predictions to guide behavior. We also discuss the possible interpretations of these findings in light of the current scientific discussion regarding the relation between masked presentation, subliminal perception and awareness measurement methods
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