8,292 research outputs found
SUVH1, a Su(var)3-9 family member, promotes the expression of genes targeted by DNA methylation.
Transposable elements are found throughout the genomes of all organisms. Repressive marks such as DNA methylation and histone H3 lysine 9 (H3K9) methylation silence these elements and maintain genome integrity. However, how silencing mechanisms are themselves regulated to avoid the silencing of genes remains unclear. Here, an anti-silencing factor was identified using a forward genetic screen on a reporter line that harbors a LUCIFERASE (LUC) gene driven by a promoter that undergoes DNA methylation. SUVH1, a Su(var)3-9 homolog, was identified as a factor promoting the expression of the LUC gene. Treatment with a cytosine methylation inhibitor completely suppressed the LUC expression defects of suvh1, indicating that SUVH1 is dispensable for LUC expression in the absence of DNA methylation. SUVH1 also promotes the expression of several endogenous genes with promoter DNA methylation. However, the suvh1 mutation did not alter DNA methylation levels at the LUC transgene or on a genome-wide scale; thus, SUVH1 functions downstream of DNA methylation. Histone H3 lysine 4 (H3K4) trimethylation was reduced in suvh1; in contrast, H3K9 methylation levels remained unchanged. This work has uncovered a novel, anti-silencing function for a member of the Su(var)3-9 family that has previously been associated with silencing through H3K9 methylation
Categorisation of Tinnitus Severity for the Mandarin Tinnitus Questionnaire
Background: The Tinnitus Questionnaire is commonly used to evaluate the psychological impact of tinnitus and has been translated into Mandarin. The original English version of the Tinnitus Questionnaire was translated into Mandarin (MTQ). The MTQ included not the same items compared with original version. Thus, MTQ should have its own severity categorization.
Aims/objectives: The objective of this research was to develop a method to categorize tinnitus patients by clinical severity using scores from the Mandarin Tinnitus Questionnaire (MTQ).
Material and Methods: A total of 192 participants with primary complaint of tinnitus were enrolled. Cross-tabulation was used to compare two categorization approaches of tinnitus severity. With the first approach, categories were assigned based purely on quartiles of MTQ scores. In the second approach, severity was determined based on Ordinal logistic regression. The two approaches were verified by comparing the consistency with clinical judgement.
Results: Categorization based on quartiles showed low consistency with clinical assessment(kappa=0.33), while categorization based on ordinal logistic regression showed good consistency with clinical assessment(kappa = 0.86).Regression-based MTQ score cut-offs were 47 for severe tinnitus.
Conclusions and significance: Tinnitus severity can be categorized accurately using ordinal logistic regression analysis of MTQ scores
Illusion optics: The optical transformation of an object into another object
We propose to use transformation optics to generate a general illusion such
that an arbitrary object appears to be like some other object of our choice.
This is achieved by using a remote device that transforms the scattered light
outside a virtual boundary into that of the object chosen for the illusion,
regardless of the profile of the incident wave. This type of illusion device
also enables people to see through walls. Our work extends the concept of
cloaking as a special form of illusion to the wider realm of illusion optics.Comment: Including a paper and its auxiliary materia
Resource-Efficient Circuit Compilation for SWAP Networks
The SWAP network offers a promising solution for addressing the limited
connectivity in quantum systems by mapping logical operations to physically
adjacent qubits. In this article, we present a novel decomposition strategy for
the SWAP network, accompanied by additional extensions that leverage an
overcomplete set of native gates. Through comprehensive evaluations, we
demonstrate the effectiveness of our protocol in reducing the gate count and
streamlining the implementation of generalized SWAP networks and Quantum Random
Access Memory (QRAM). Our research tackles the challenges posed by limited
connectivity, leading to improved performance of SWAP networks and simplified
QRAM implementation, thereby contributing to the advancement of quantum
computing technologies.Comment: 23 pages, 15 figure
Estimate haplotype frequencies in pedigrees
BACKGROUND: Haplotype analysis has gained increasing attention in the context of association studies of disease genes and drug responsivities over the last years. The potential use of haplotypes has led to the initiation of the HapMap project which is to investigate haplotype patterns in the human genome in different populations. Haplotype inference and frequency estimation are essential components of this endeavour. RESULTS: We present a two-stage method to estimate haplotype frequencies in pedigrees, which includes haplotyping stage and estimation stage. In the haplotyping stage, we propose a linear time algorithm to determine all zero-recombinant haplotype configurations for each pedigree. In the estimation stage, we use the expectation-maximization (EM) algorithm to estimate haplotype frequencies based on these haplotype configurations. The experiments demonstrate that our method runs much faster and gives more credible estimates than other popular haplotype analysis software that discards the pedigree information. CONCLUSION: Our method suggests that pedigree information is of great importance in haplotype analysis. It can be used to speedup estimation process, and to improve estimation accuracy as well. The result also demonstrates that the whole haplotype configuration space can be substituted by the space of zero-recombinant haplotype configurations in haplotype frequency estimation, especially when the considered haplotype block is relatively short
Photoacoustic signal enhancement in dual-contrast gastrin-releasing peptide receptor-targeted nanobubbles
Translatable imaging agents are a crucial element of successful molecular imaging. Photoacoustic molecular imaging relies on optical absorbing materials to generate a sufficient signal. However, few materials approved for human use can generate adequate photoacoustic responses. Here we report a new nanoengineering approach to further improve photoacoustic response from biocompatible materials. Our study shows that when optical absorbers are incorporated into the shell of a gaseous nanobubble, their photoacoustic signal can be significantly enhanced compared to the original form. As an example, we constructed nanobubbles using biocompatible indocyanine green (ICG) and biodegradable poly(lactic-co-glycolic acid) (PLGA). We demonstrated that these ICG nanobubbles generate a strong ultrasound signal and almost four-fold photoacoustic signal compared to the same concentration of ICG solution; our theoretical calculations corroborate this effect and elucidate the origin of the photoacoustic enhancement. To demonstrate their molecular imaging performance, we conjugated gastrin-releasing peptide receptor (GRPR) targeting ligands with the ICG nanobubbles. Our dual photoacoustic/ultrasound molecular imaging shows a more than three-fold enhancement in targeting specificity of the GRPR-targeted ICG nanobubbles, compared to untargeted nanobubbles or prostate cancer cells not expressing GRPR, in a prostate cancer xenograft mouse model in vivo
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