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As a promising new molecular imaging technique, mass spectrometry imaging (MSI) has attracted more and more attention in the field of biomedicine. A method of air flow assisted ionization-ultra high resolution mass spectrometry-based mass spectrometric imaging (AFAI-MSI) was developed to profile endogenous metabolites in rat kidney tissue in this study. Rat kidneys were collected and cut into frozen tissue sections, and then were analyzed on an AFAI-MSI system operated in positive ion mode using acetonitrile- isopropanol-water (4:4:2, V/V, 5 μL min−1) as spray solvent, nitrogen gas as spray gas (0.6 MPa) and air as assisting gas (45 L min−1). The mass range and resolution were set to be 70–1000 Da and 70000, respectively. As a result, a total of 38 metabolites, ranging from 103 to 107 in signal strength and belonging to different metabolite types, including organic amines, sugars, vitamins, peptides, neurotransmitters, organic acids, phospholipids, sphingolipids, glycerides, and cholesterol esters, were identified and imaged to characterize their tissue-specific distribution in kidney tissues. Some metabolites, such as choline, acetycholine, betaine, phosphocholine, and glycerolphosphocholin were found to have distinct distribution along the cortex-medulla axis, which may be involved in the formation of osmotic pressure gradient in the kidney. The proposed ultra high resolution mass spectrometry based AFAI-MSI method can work without sample pretreatment, showing high sensitivity and wide metabolite coverage, and is expected to provide a new analytical approach in the research of in situ characterization and metabolic regulation mechanism of endogenous metabolites in kidney.

To understand the infection status of soil-transmitted nematodes in Xinchang County, so as to offer the evidence for the formulation of control measures.The infection of soiltransmitted nematodes in residents was investigated by using the Kato-Katz method and cellophane anal swab.A total of 3 069 people were examined in 2009, 2012 and 2017, of which 1 520 people were male and 61 people were infected, with the infection rate of 4.01%; 1 549 were women and 54 people were infected, with the infection rate of 3.48%. The infection rates of soil-transmitted nematodes in 2009, 2012 and 2017 were 4.60%, 4.29% and 2.35%, respectively, and the total infection rates were decreased (χThe rate of soil-transmitted nematode infection in Xinchang County is declining, and it is at a low epidemic level.[

Arrays of sharp conical spike microstructures are created by repeatedly irradiating silicon surfaces with focused femtosecond laser pulses in SF6. The absorbance of light is increased to approximately 90% in a wavelength range from the near ultraviolet (0.25 m) to the near infrared (2.5 m) by the microstructured silicon surface. The microstructured surface presents pitch-black because of enhanced absorption with a broad wavelength range, which is called black silicon. The unique microstructure morphology of black silicon surface formed by femtosecond laser can also bring a lot of other surface functions, for example, self-cleaning and field emission. These functions make black silicon highly desirable in solar energy, detectors and other fields. Therefore, the forming mechanism and conditions of fabrication optimization for black silicon microstructure have always been the focus of research. In our work, the sample is moved by motor-controlled stage while the laser beam is fixed. In the case of laser beam scanning, arrays of sharp conical spikes on the silicon are manufactured in 70 kPa SF6. The aim of the experiment is to find how to optimize the distribution of the laser energy in a number of laser accumulation pulses (the combination of single pulse energy and pulse number) to control the surface morphology of the black silicon. Experimental results show that there appears a bottleneck effect of morphology size growth with the increase of laser irradiation (improving the single pulse energy or increasing pulse accumulation number). Excessive energy accumulation brings no extra effect on optimizing and controlling of microstructure morphology on the surface. Based on theoretical results obtained from a physical model we proposed, we find that the reason for this phenomenon is that the microstructure morphology induced by former sequence pulse modulates the laser energy absorption of current laser pulse, and changes the laser ablation efficiency of the current pulse. According to this physical mechanism, we propose a new way of optimizing surface morphology, with fixing the total laser irradiation energy. And the size and distribution of surface morphology can be achieved by optimizing the distribution of the laser energy in a number of laser accumulation pulses. This approach can not only improve the efficiency of silicon surface preparation of microstructures but also reduce the surface defects and damage. Furthermore, the proposed method can reduce the energy consumption in the process of femtosecond machining. It is of great significance for the engineering application of black silicon.