基于Linux图像处理平台的家用型尿液检测仪表

随着中国人口持续增长以及老龄化问题日益严重,就医难就医贵已成为一个社会难题。尿液检测最常规的检验手段之一,可以为诸多疾病的诊断提供重要信息。本文根据传统的尿液干化学分析仪的基本原理,以尿液检测试纸作为图像分析的对象,采用应用广泛、低成本的嵌入式方案基于OpenCV搭建嵌入式图像处理平台。选用具有ARM9核的处理器(S3C2440A)的MINI2440开发板,在Linux操作系统的基础上搭建该图像处理平台。通过测试和仿真证明设计出的尿液检测仪表效果与性能良好。     

Nitrate leaching losses and pasture yields as affected by different rates of animal urine nitrogen returns and application of a nitrification inhibitor—a lysimeter study

Nitrate (NO₃⁻) leaching and water contamination is a major environmental issue around the globe. In grazed grassland, most of the nitrate leaching occurs under the animal urine patch areas because of high nitrogen (N) loading rates. The aim of this study was to determine NO₃^–-N leaching losses and pasture responses as affected by different animal urine-N loading rates and application of a nitrification inhibitor, dicyandiamide (DCD). Undisturbed monolith lysimeters (50 cm diameter by 70 cm deep) of a free-draining stony soil (Pallic orthic brown soil; Udic Haplustept loamy skeletal) with a mixture of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) were used for the study. Results showed that total NO₃^–-N leaching losses increased significantly (P < 0.01) from 22.8 to 59.7, 188.1 and 254.9 kg NO₃⁻-N ha⁻¹, when urine N was applied at 0 (Control), 300, 700 and 1,000 kg N ha⁻¹, respectively, without DCD. The application of DCD to the corresponding treatments significantly (P < 0.01) reduced the total NO₃⁻-N leaching losses to 12.4, 9.9, 75.3 and 139.0 kg N ha⁻¹, respectively, resulting in an average reduction of 63%. Pasture yield increased linearly with increasing urine-N application rates and the application of DCD resulted in an average 25% increase in pasture dry matter production. The average N offtake was increased by 32% with the application of DCD, confirming the effectiveness of the inhibitor in improving the N cycle. These results indicate that the DCD nitrification inhibitor technology has the potential to be a valuable nitrogen management tool in different grazed pasture systems (e.g. sheep, beef cattle and dairy cattle) to mitigate NO₃⁻ leaching and improve sustainable production.     

Role of ureolytic bacteria on corrosion behavior of fretted grade 880 mild steel rail

Corrosion due to toilet droppings has a pronounced effect on rails. In the present study, corrosion behavior of Mild Steel (Grade 880) was evaluated by bacterial spray chamber in presence of bacteria, and the impact of air bacteria on fretted steel was investigated. The production of ammonia and pH of medium in presence of microbes were monitored at regular intervals. The pH was observed to rise to a value of 9.6, with increase in estimated ammonia content to 6000 ppm. Conversion of FeOOH in bare steel to Fe₂O₃ and FeO as a result of corrosive attack by bacterial species revealed from XRD data. Bacterial contribution was significant in augmenting the rate of corrosion in fretted mild steel samples. SEM reveals the occurrence of pitting on fretted steel under bacterial spray chamber environment. The present study concludes by inferring that the presence of ureolytic bacteria enhances corrosion in fretted Mild steel (Grade 880).     

Low-cost struvite production using source-separated urine in Nepal

This research investigated the possibility of transferring phosphorus from human urine into a concentrated form that can be used as fertilizer in agriculture. The community of Siddhipur in Nepal was chosen as a research site, because there is a strong presence and acceptance of the urine-diverting dry toilets needed to collect urine separately at the source. Furthermore, because the mainly agricultural country is landlocked and depends on expensive, imported fertilizers, the need for nutrient security is high. We found that struvite (MgNH₄PO₄·6H₂O) precipitation from urine is an efficient and simple approach to produce a granulated phosphorus fertilizer. Bittern, a waste stream from salt production, is a practical magnesium source for struvite production, but it has to be imported from India. Calculations show that magnesium oxide produced from locally available magnesite would be a cheaper magnesium source. A reactor with an external filtration system was capable of removing over 90% of phosphorus with a low magnesium dosage (1.1 mol Mg mol P), with coarse nylon filters (pore width up to 160 ± 50 μm) and with only one hour total treatment time. A second reactor setup based on sedimentation only achieved 50% phosphate removal, even when flocculants were added. Given the current fertilizer prices, high volumes of urine must be processed, if struvite recovery should be financially sustainable. Therefore, it is important to optimize the process. Our calculations showed that collecting the struvite and calcium phosphate precipitated spontaneously due to urea hydrolysis could increase the overall phosphate recovery by at least 40%. The magnesium dosage can be optimized by estimating the phosphate concentration by measuring electrical conductivity. An important source of additional revenue could be the effluent of the struvite reactor. Further research should be aimed at finding methods and technologies to recover the nutrients from the effluent.     

TRPO萃取荧光法测定尿和水中铀

近年来,国内多采用磷酸三丁脂、乙酸乙酯~([1])和三辛基氧膦(TOPO)萃取法~([2])。及激光荧光法~([3])测定尿和水中铀。文献[4]较全面地介绍了铀的荧光法测定。文献[5]报道了使用三烷基(混合)氧膦(TRPO)代替TOPO萃取和Br-PADAP分光光度法测定矿石、矿渣中的微量铀,取得了与TOPO同样的分离效果。文献[6]较详细地研究了用TRPO从高放废水中萃取U、Np、Pu、Am、Cm、Pm和Tc,探讨了用这种方法处理超铀废水的可能性。TRPO为磷肥厂产品,较TOPO价廉易得。     

Effect of urine volume on nitrate leaching in the northeast USA

To investigate how the urine volume (i.e. size of cow) affects how much NO₃-N is leached from a urine deposition in the climatic conditions of the northeast USA, a field study using large drainage lysimeters to measure NO₃-N leaching loss from synthetic urine applied in spring, summer and fall in 1-, 2-, and 3-l volumes to an orchardgrass (Dactyls glomerata L., c.v. Pennlate) sward was conducted from April 1997 to March 1999. The study site was located in central Pennsylvania on a Hagerstown silt loam soil (fine, mixed, mesic Typic Hapludalf). It was found that increasing urine volume increased the amount of urine N leached but had no significant effect on the apparent percent of urine N leached. The apparent percent of urine N leached was 25% averaged over all treatment times and volumes and was 21% for spring and summer applied urine and 32% for fall applied urine.     

Analysis of 5-hydroxymethyl-2-furoic acid (HMFA) the main metabolite of alimentary 5-hydroxymethyl-2-furfural (HMF) with HPLC and GC in urine

A liquid chromatographic method with UV detection was developed to analyse 5-hydroxymethyl-2-furfural and its main metabolite 5-hydroxymethyl-2-furoic acid in urine. For the analysis on a reversed phase column was used with 5% methanol in water and 5 mM tetramethylammoniumhydrogen sulphate as ion-pair reagent as eluent. The detection was done at the UV absorption maximum of HMFA at 255 nm. The limit of quantification for HMFA was 7 mg/L with a recovery of 89%. For sample preparation the urine was centrifuged and the supernatant diluted with water. Three hundred samples of human urine were analysed. The concentration of HMFA was in the range of 0–100 mg/L with most of the samples around 10 mg/L.     

Influences of biofluid sample collection and handling procedures on GC–MS based metabolomic studies

Sample collection procedures of pharmacology and toxicology studies might have a great impact on interpretation of metabolomic study results. Characterization of range variation among sample collection methods is necessary to prevent misinterpretation, as is use of optimal methods in animal experiments to minimize biological/technical variation. Here, we investigated the influence of urine and plasma sample collection and handling procedures on GC–MS based metabolomic studies as follows: for urine, pooling period and tube conditions during collection; for plasma, sampling sites, anesthesia and anticoagulants. Metabolic profiles of urine varied dramatically depending on urine pooling period and tube conditions, underscoring the importance of determining appropriate sampling periods in consideration of diurnal effects and targets of effect/toxicity, and suggesting it would be preferable to keep tubes in metabolic cages under iced conditions for urine sampling. Metabolic profiles of plasma differed depending on blood sampling sites. Anesthesia was not effective in reducing individual variation, although the anesthesia was beneficial in reducing discomfort in rats. In GC–MS based metabolomic studies, we recommend that EDTA be used as anticoagulant in plasma sample preparation, because peaks derived from heparin might overlap with endogenous metabolites, which may induce inter-sample variation. The present study demonstrated that biofluid sample collection and handling procedures provide great impact on metabolic profiles, at the very least for minimizing biological/technical variation, sampling period for urine collection should not be set as a short period, and the use of EDTA is recommended as anticoagulant in preparing plasma for analysis by GC–MS.