Genome editing using programmable nucleases is revolutionizing life science and medicine. Off-target editing by these nucleases remains a considerable concern, especially in therapeutic applications. ...Here we review tools developed for identifying potential off-target editing sites and compare the ability of these tools to properly analyze off-target effects. Recent advances in both in silico and experimental tools for off-target analysis have generated remarkably concordant results for sites with high off-target editing activity. However, no single tool is able to accurately predict low-frequency off-target editing, presenting a bottleneck in therapeutic genome editing, because even a small number of cells with off-target editing can be detrimental. Therefore, we recommend that at least one in silico tool and one experimental tool should be used together to identify potential off-target sites, and amplicon-based next-generation sequencing (NGS) should be used as the gold standard assay for assessing the true off-target effects at these candidate sites. Future work to improve off-target analysis includes expanding the true off-target editing dataset to evaluate new experimental techniques and to train machine learning algorithms; performing analysis using the particular genome of the cells in question rather than the reference genome; and applying novel NGS techniques to improve the sensitivity of amplicon-based off-target editing quantification.
Background
The aim of this study was to investigate the prevalence of epidemiologic and physician‐diagnosed pollen‐induced AR (PiAR) in the grasslands of northern China and to study the impact of the ...intensity and time of pollen exposure on PiAR prevalence.
Methods
A multistage, clustered and proportionately stratified random sampling with a field interviewer‐administered survey study was performed together with skin prick tests (SPT) and measurements of the daily pollen count.
Results
A total of 6043 subjects completed the study, with a proportion of 32.4% epidemiologic AR and 18.5% PiAR. The prevalence was higher in males than females (19.6% vs 17.4%, P = .024), but no difference between the two major residential and ethnic groups (Han and Mongolian) was observed. Subjects from urban areas showed higher prevalence of PiAR than rural areas (23.1% vs 14.0%, P < .001). Most PiAR patients were sensitized to two or more pollens (79.4%) with artemisia, chenopodium, and humulus scandens being the most common pollen types, which were similarly found as the top three sensitizing pollen allergens by SPT. There were significant regional differences in the prevalence of epidemiologic AR (from 18.6% to 52.9%) and PiAR (from 10.5% to 31.4%) among the six areas investigated. PiAR symptoms were positively associated with pollen counts, temperature, and precipitation (P < .05), but negatively with wind speed and pressure P < .05).
Conclusion
Pollen‐induced AR (PiAR) prevalence in the investigated region is extremely high due to high seasonal pollen exposure, which was influenced by local environmental and climate conditions.
A simple polarization reconfigurable printed monopole antenna is proposed for wireless applications. Conducting strips are used to connect to the ground plane providing the necessary additional modes ...for circular polarization. Linear polarization, right-hand or left-hand circular polarization can be realized using only two PIN diodes, which connect to the ground plane, minimizing their effect on radiation characteristics. The mechanism is described, and key antenna parameters are studied and optimized. The antenna is prototyped and tested for all polarization configurations.
ZnO nanowire (NW) visible-blind UV photodetectors with internal photoconductive gain as high as G ∼ 108 have been fabricated and characterized. The photoconduction mechanism in these devices has been ...elucidated by means of time-resolved measurements spanning a wide temporal domain, from 10-9 to 102 s, revealing the coexistence of fast (τ ∼ 20 ns) and slow (τ ∼ 10 s) components of the carrier relaxation dynamics. The extremely high photoconductive gain is attributed to the presence of oxygen-related hole-trap states at the NW surface, which prevents charge-carrier recombination and prolongs the photocarrier lifetime, as evidenced by the sensitivity of the photocurrrent to ambient conditions. Surprisingly, this mechanism appears to be effective even at the shortest time scale investigated of t < 1 ns. Despite the slow relaxation time, the extremely high internal gain of ZnO NW photodetectors results in gain-bandwidth products (GB) higher than ∼10 GHz. The high gain and low power consumption of NW photodetectors promise a new generation of phototransistors for applications such as sensing, imaging, and intrachip optical interconnects.
Abstract The pathogenesis of Parkinson's disease is characterized by progressive degeneration of dopaminergic neurons in substantia nigra (SNpc). FLZ, a novel synthetic squamosamide derivative from a ...Chinese herb, has been shown to have neuroprotective effects in experimental Parkinson's disease (PD) models. However, it is still unclear whether FLZ protects against PD through regulating the function of dopaminergic system. In this study, we carried out a set of in vitro and in vivo experiments to address these questions. Oral administration of FLZ significantly improved motor dysfunction of mice challenged by MPTP. The beneficial effects of FLZ on motor behavior attributed to the elevation of dopamine level in striatum, tyrosine hydroxylase (TH)-positive cells, and TH activity in the middle brain of mouse. Mechanism study showed that treatment of FLZ increased the phosphorylation of activating protein kinase B (Akt) and mammalian target of rapamycin (mTOR). Using LY294002 to block phosphoinositide 3-kinases (PI3K)/Akt signaling pathway prevented the phosphorylation of mTOR and attenuated the neuroprotection of FLZ in MN9D cells challenged by MPP+ . In addition, FLZ reduced the expression of RTP801, an important protein in PD, in mice and cells intoxicated by MPTP/MPP+ . Taken together, these results revealed a novel role that FLZ elevated TH expression and activity in dopaminergic neuron through activation of Akt/mTOR survival pathway and inhibition of RTP801 in MPTP/MPP+ -induced PD models. The data also provided evidence that FLZ had potent neuroprotecive effects and might become a new promising anti-PD drug.
GaAs-on-Si epitaxial crystal quality has historically been limited by a number of growth-related defects. In particular, antiphase domain boundaries (APBs) can nucleate at the GaAs/Si interface and ...propagate throughout the entire GaAs layer. Still little is known about how thermal processing can affect the APB density in GaAs. In this study, GaAs was grown on nominally on-axis Si(001) by metal–organic chemical vapor deposition. The effect of ex situ post-growth annealing was evaluated for a temperature range of 550–700 °C. It was found that upon annealing the APB density was decreased significantly. The rate of APB density decrease was found to be temperature dependent. At annealing temperatures of 650 °C and above, the APB density was reduced from 0.10 μm
−1
to approximately 0.010 μm
−1
in less than 10 min. The activation energy for APB dissolution was determined to be 3.8 eV. The mechanism of APB dissolution is discussed.
The soluble complexes formed between hydrolyzed soybean protein and calcium at pH 7.4 were investigated using dialysis, gel chromatography, and Fourier transform infrared spectrometry (FTIR). The ...results demonstrate that the amount of calcium bound was significantly different for soybean protein hydrolysates obtained using the proteases neutrase, flavourzyme, protease M, and pepsin. Maximum levels of calcium binding (66.9 mg/g) occurred with hydrolysates produced using protease M. Peptide fragments exhibiting high calcium binding capacity had molecular weights of either 14.4 kDa or 8 to 9 kDa, and the calcium binding capacity was linearly correlated with carboxyl group content (R²= 0.8204). FTIR experiments revealed that upon binding calcium, the amide I band underwent a shift to lower wave numbers. A wide, intense Ca-O absorption band also appeared between 400 and 100 cm⁻¹ in the far-infrared spectrum. The width and intensity of this band increased after treatment of samples with glutaminase. The amount of bound calcium was related to both the molecular weight of the peptides and to the carboxyl group content, and the most likely sites for calcium binding are the carboxyl groups of Asp and Glu.
Properties near public transportation systems are usually sold at a premium owing to the willingness of firms and people to pay for access to workplace and leisure. However, the economic impact of ...major infrastructure investments remains an empirical question plagued by identification issues. We investigate the economic impacts of a major transportation development project currently under construction in Hong Kong: the Tuen Mun–Chek Lap Kok tunnel, namely the effects on property prices of the expansion of the regional road network in the Greater Bay Area. We identify a significant accessibility premium well before the tunnel is completed. There is also a change in market structure of increased preference for residential property in areas closer to the tunnel, reflected by higher price appreciation. The findings help guide urban planning and public investment decisions, as well as the design and implementation of land value capture policy.
DNA methylation at imprinting control regions (ICRs) is established in gametes in a sex-specific manner and has to be stably maintained during development and in somatic cells to ensure the correct ...monoallelic expression of imprinted genes. In addition to DNA methylation, the ICRs are marked by allele-specific histone modifications. Whether these marks are essential for maintenance of genomic imprinting is largely unclear. Here, we show that the histone H3 lysine 9 methylases G9a and GLP are required for stable maintenance of imprinted DNA methylation in embryonic stem cells; however, their catalytic activity and the G9a/GLP-dependent H3K9me2 mark are completely dispensable for imprinting maintenance despite the genome-wide loss of non-imprinted DNA methylation in H3K9me2-depleted cells. We provide additional evidence that the G9a/GLP complex protects imprinted DNA methylation by recruitment of de novo DNA methyltransferases, which antagonize TET dioxygenass-dependent erosion of DNA methylation at ICRs.
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•ESCs lacking G9a and GLP display loss of DNA methylation from ICRs•The enzymatic activity of G9a/GLP is dispensable for imprinted DNA methylation•G9a/GLP stabilize imprinting by recruitment of de novo DNA methyltransferases to ICRs•Recruitment of DNMTs to ICRs antagonizes TET-dependent loss of DNA methylation
Loss of allele-specific DNA methylation from imprinting control regions leads to unbalanced gene expression and disease. Here, Zhang et al. show that the KMT enzymes G9a and GLP stabilize imprinted DNA methylation in embryonic stem cells by recruitment of de novo DNA methyltransferase enzymes, which counteract TET dioxygenase-dependent demethylation pathways.
A printed triangular monopole antenna with wideband circular polarization is presented. The wideband circular polarization is achieved by asymmetrical excitation of a triangular ground plane and ...planar triangular monopole. The combined radiation provides a wide axial-ratio bandwidth spanning from 1.42 to 2.7 GHz (62%). A parametric study of key geometric parameters is given for clear understanding of the radiation mechanism.
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