Biomedical subjects

Hongtu Xie

Publications and source records attributed to Hongtu Xie.

5 recordsLinked to original sources

PubMed2006

[Soil carbohydrates: their determination methods and indication functions].

Soil carbohydrates are the important component of soil organic matter, and play an important role in soil aggregation formation. Their hydrolysis methods involve sulfur acid (H2SO4), hydrochloric acid (HCl), and trifluoroacetic acid (TFA) hydrolysis, and their determination methods include colorimetry, gas-liquid chromatography (GLC) , high performance liquid chromatography (HPLC), and high performance anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD). This paper summarized the methods of carbohydrates' hydrolysis, purification and detection, with focus on the derived methods of GLC, and briefly introduced the indication functions of carbohydrates in soil organic matter turnover.

Carbohydrates↗

PubMed2005

A gas chromatographic/mass spectrometric method for tracing the microbial conversion of glucose into amino sugars in soil.

Amino sugars in soils are heterogeneous and have been used as microbial residue biomarkers to investigate the microbial contribution to soil organic matter. However, it is not clear what the available carbon source is and how glucose is utilized for the synthesis of soil amino sugars. This paper presents a new gas chromatography/mass spectrometry (GC/MS) approach for the identification of 13C incorporation into three amino sugars, D-glucosamine, D-galactosamine, and muramic acid, in soil incubated with U-13C-glucose. Method evaluation showed that the chemical ionization (CI) mode was suitable for all these amino sugars, but that electron impact (EI) mode was applicable only to glucosamine and galactosamine. The 13C conversion rate was estimated based on the abundance ratio of the ions corresponding to the masses of the ions F+n and F (where n is the skeleton carbon number in the fragment ions F of the amino sugars) and calculated as atom percentage excess. The reproducibility of the method was excellent and clearly adequate for the present purpose. In addition, the new approach is highly accurate as tested with mixtures of U-13C-glucose and natural glucose.

Amino Sugars↗

PubMed2003

[New quantificational indexes in modern study of soil organic matter].

In modern study of soil organic matter, many new quantificational indexes and relevant testing methods, e.g., DOC, WSOC, HWC, ROC, MBC, MBN, PMC, PMN, Glu, Gla, Man, Mur, delta 13C, and CPMI, came forth with deepening study. Because they are disorderly and unsystematic, it is necessary to clarify these indexes. This paper summarized their origin, concept, and testing method, which is of significance in the modern study of soil organic matter.

Organic Chemicals↗

PubMed2003

[Research advances on controlled-release mechanisms of nutrients in coated fertilizers].

Using encapsulation techniques to coat easily soluble fertilizers is an important way to improve fertilizer use efficiency while reduce environmental hazards. Based on a wide range of literature collection on coated fertilizer research, the theories, processes, and characters of nutrient controlled-release from coated fertilizer were discussed, and the factors affecting nutrient controlled-release and the mathematical simulations on it were reviewed. The main tendencies related to this research in China were also put forward.

Delayed-Action Preparations↗

PubMed2002

[Effects of applying nitrogen fertilizer at different stages in ploughed furrow on dry matter production and yield of rice].

The effects of applying nitrogen fertilizer in ploughed furrow at different stages on dry matter production and yield of rice were studied in a field experiment in 1999. The results showed that applying N fertilizer at booting stage (BS) had better effects on dry weight (2.9 g.hill-1) of leaf, stem and whole plant than at panicle primordia formation stage (PPFS), tillering stage (TS) and regular N fertilization (RF). Meanwhile, the dry weight of leaf and sheath as well as the leaf area index (LAI, 8.9) could be maintained at a high level for a relative long time in BS treatment, compared with PPFS, TS and RF treatments. Similar phenomenon was observed in the growth velocity (0.73 g.d-1.hill-1) of stem and whole plant, and the dry weight (10434 kg.hm-2) of seed. The grain yield of rice followed the sequence of BS > or = PPFS > TS > or = RF. Thus, the optimum stage of applying N fertilizer in ploughed furrow was the booting stage.

Agriculture↗