Pan-cancer analysis of DNA epigenetic modifications by hydrophilic interaction liquid chromatography-tandem mass spectrometry

Accumulating evidence in recent years indicates that DNA methylation(5-methyl-2-deoxycytidine,5-mdC) and hydroxymethylation(5-hydroxymethyl-2-deoxycytidine, 5-hmd C) have been implicated in various biological processes, and the aberrations of these DNA cytosine modifications is tightly associated with cancer. N6-methyl-2-deoxyadenosine(m~6dA), as a newly discovered epigenetic modification in genome of mammals, has been demonstrated to play vital regulatory roles in tumorigenesis. However, the content information of m~6dA in human tumor tissues is still limited and pan-cancer analysis of these DNA epigenetic modifications is lacked. Herein, we developed a sensitive and robust stable isotopediluted hydrophilic interaction liquid chromatography-tandem mass spectrometry(HILIC-MS/MS) method for accurate quantification of m~6dA, 5-mdC and 5-hmdC in genomic DNA from 82 pairs of human tumor tissues and matched tumor-adjacent normal tissues. The types of tumors included esophagus cancer, lung cancer, breast cancer, liver cancer, pancreatic cancer, gastric cancer, stromal tumor and colorectal cancer.Compared to the normal tissues, we revealed the level of m6dA was increased in tumor tissues of esophagus cancer, lung cancer and liver cancer, whereas the level of m~6dA was diminished in tumor tissues of pancreatic cancer and gastric cancer;while the contents of 5-mdC and 5-hmdC exhibited significant decrease in tumor tissues of most types of cancer. It is worth noting that we revealed, for the first time,the content of genomic m~6dA in pancreatic cancer, stromal tumor and colorectal cancer. The significant changes of these DNA epigenetic modifications indicate they may serve as indicators of cancers. In addition, this study will benefit for better understanding of the regulatory roles of these DNA epigenetic modifications in cancers.

Effects of spray adjuvants and operation modes on droplet deposition and elm aphid control using an unmanned aerial vehicle

A conventional spraying mode and a fully autonomous fruit tree operation mode using a model DJ T30 unmanned aerial vehicle(UAV)were used to control aphids control on elm trees and to clarify the distribution of droplets in elm trees sprayed by a UAV.The effects of six aviation spray adjuvants on elm canopy droplet deposition and aphid control were evaluated.ImageJ software was used to analyze and measure the droplet density and deposition of water sensitive paper in two modes;this was done to calculate the droplet uniformity,depositional penetration,and droplet penetration,and to verify the aphid control effect.The results showed that the droplet density increased by 79.7%-100.7% in the upper canopy and 0-394.1%in the lower canopy without adjuvants in the fully autonomous fruit tree operation mode.The upper canopy deposits increased by 65.7%-179.3%,and the lower canopy increased by 0-152.8%.When adjuvants were added,the droplet density in the upper canopy increased by 49.7-56.1%using Jiexiaofeng(JXF),and the lower canopy increased by 138.2%-177.8% using JXF,45.8%-141.3%using Beidatong(BDT),45.5%-92.9% using Gongbei(GB),0-93.5% using Maisi(MS),and 0-95.2%using Manniu(MN).The deposits of the upper canopy increased by 888.1-1154.2% using JXF,0-1298.3% using MN,0-343.9%using BDT,0-422.5% using GB,0-580.3% using MS.The lower canopy increased by 746.4%-1426.0%using JXF,226.2%-231.0% using BDT,435.8%-644.0% using GB,255.0%-322.4%using MS,and 249.3%-360.0%using MN.When JXF was added,the droplet uniformity,droplet penetration and depositional penetration were better than when using other adjuvants.The effects of JXF,BDT and GB in controlling aphids was significantly better than other adjuvants(p<0.05).The following control effects were observed;94.1% with JXF,93.1% with BDT,and 93.3% with GB after 3 d of application,and 97.9% with JXF,95.6% with BDT,and 97.1% with GB after 7 d of application.At the same time,the application of the fully autonomous fruit tree operation mode and JXF can effectively improve the density and deposits,which will produce a superposition optimization effect.Our study focuses on the prevention and control of elm aphid infestations based on the operation mode of a UAV and aviation spray adjuvants,which can provide a baseline for the control of diseases and insect pests using UAVs in agriculture and forestry.

Study of the Characteristics and Suppression of EMI of Inverter with SiC and Si Devices

The paper systematically studies the impacts of two major factors:device switching actions and inverter switching frequency on the whole EMI spectrum.Several powerful experimental results of electromagnetic interference(EMI)in voltage source inverter(VSI)with SiC and Si devices are provided.As far as the influence of switching actions is concerned:faster switching speed will generate higher EMI noise levels in the high frequency range,and ringing in the device switching will also make the EMI noise near the ringing frequency range worse.In the meantime,increasing of the switching frequency of the inverter will result in a higher EMI noise peak for the whole EMI spectrum.In order to suppress the EMI noise of the converter to meet standards,Random PWM(RPWM)and EMI filters are adopted.With RPWM,the EMI current can drop a few more dB than that with SVPWM,which makes the filter work better.Also,as extra attenuation can be provided,it provides the benefit of reducing the weight and volume of the inductor of the filter.Therefore,the combination of an advanced modulation strategy and EMI filter is proposed for suppressing of EMI noise in an inverter.

Modular Design Method for Motor Drives

This paper introduces the concept of modular design methodology for hardware design and development of motor drives.The modular design process is first introduced separating the hardware development into three parts:controller,mother board and phase-leg module.The control and circuit function can be decoupled from the phase-leg module development.The hardware update can be simplified with the phase-leg module development and verification.Two design examples are used to demonstrate this method:a DC-fed motor drive with Si IGBTs and an AC-fed motor drive with SiC devices.Design of DC-fed motor drive aims at developing the converter with customized IGBT package for high temperature.Experience with development of the converter with commercial IGBTs simplifies the process.As the AC-fed motor drive is a more complex topology using more advanced devices,the modular design method can simplify and improve the development especially for new packaged devices.Also,the modular design method can help to study the electromagnetic interference(EMI)issue for motor drives,which is presented with an extra design example.