Drainage history and land use pattern of a Swedish river system — their importance for understanding nitrogen and phosphorus load

During the 19th and the first half of the 20th century, approximately 300 km² of lakes and wetlands, representing 29% of the River Kavlingean catchment in Southern Sweden, were drained to make land available for agriculture. Published accounts of nutrient loads from the catchment indicated that until the mid 20th century, factories and urban point sources were the major contributors of both nitrogen and phosphorus. By the middle of the 20th century, the construction of sewage treatment plants had effectively reduced phosphorus pollution. Concurrently, the land drained in the previous century underwent a more intense cultivation, with productivity being maintained by commercial fertilizers. Subsequently, net nutrient loads from agriculture continued to increase, reaching an annual load of 2652 tons total-nitrogen and 70 tons total-phosphorus for the River Kävlingeån. Whilst high nutrient leakage from agricultural watersheds may be a problem which is only recently recognized, it had its origins in nearly a hundred years of commonly accepted agricultural policy.To assess the importance of agriculture as the major source of nutrients to the River Kävlingeån system, three tributary catchment areas, differing in terms of their land use patterns (high, medium and low intensity of agricultural use), were studied and compared with literature figures. Results indicated that agricultural nutrient loss areal coefficients were substantially higher than the literature figures, demonstrating the role of agriculture as source of nutrients to the River Kävlingeån system. The agricultural land use policies of the last fifty years were revealed to be most important with regard to this role. Of such land use policies, the cultivation of the last 10–15% of land employed for agricultural use (primarily riparian ecotones) may be of most significance. The literature indicates that intense agricultural use of this final 10–15% may account for a ca. 50% increase in nitrogen loss. This suggests that one solution to the problem of agricultural diffuse pollution may lie in the restoration and sustainable management of riparian ecotones of agricultural streams.     

Narrow-leaved lupine seeds as a dietary protein source for fattening rabbits: a comparison with white lupine seeds

Lupine seeds have the potential to be an alternative to imported dietary proteins. In rabbits, it has been indicated that White lupine seed (WLS) is a suitable protein source. Other lupine species, for example, narrow-leaved lupine seed (NLS), have not yet been tested in rabbit diets. Two experiments were carried out to evaluate the effect of the dietary inclusion of NLS on growth performance, sanitary risk index (SRI), coefficients of total tract apparent digestibility (CTTAD) and nitrogen output in fattening rabbits. Narrow-leaved lupine was compared with WLS as a main protein source. For Experiment I, a total of 198 Hyplus rabbits (37 days of age) were allocated into two groups (99 rabbits per group), fed the WLS I diet (120 g/kg of WLS cv. Amiga) or the NLS I diet (150 g/kg of NLS cv. Probor), and used for performance and carcass trait evaluations. In addition, the CTTAD of the diets and the nitrogen output were determined in 10 Hyplus rabbits per treatment (37 days of age). For Experiment II, a total of 180 Hyplus rabbits (32 days of age) were allocated into two groups (90 rabbits per group), fed the WLS II diet (120 g/kg of WLS cv. Amiga) or the NLS II diet (130 g/kg of NLS cv. Primadona), and used for performance and carcass trait evaluations. In addition, the CTTAD of the diets was determined in 10 Hyplus rabbits per treatment (32 days of age). Regardless of the treatment, the dietary inclusion of NLS had a negative effect on growth of the rabbits. The nitrogen excretion and coefficients of nitrogen retention of rabbits were not affected by the treatments. In Experiment I, SRI (37 to 80 days of age) was higher in rabbits fed the NLS I diet than in those fed the WLS I diet (38.4% v. 23.2%, respectively; P = 0.031). Similarly, in Experiment II (32 to 74 days of age), SRI was higher in rabbits fed the NLS II diet than in rabbits fed the WLS II diet (37.8% v. 23.3%, respectively; P = 0.052). In conclusion, regardless of the variety, the dietary inclusion of NLS had no negative effect on the nitrogen output or dressing-out percentage of rabbits when compared to those of rabbits fed the WLS diets. With respect to the SRI and performance, however, NLS did not provide a satisfactory outcome.     

Puddling: from natural history to understanding how it affects fitness

The term ‘puddling’ includes feeding on (dried) mud and various excrements and secretions of vertebrates, and carrion. It is thought to be a form of supplementary feeding, not targeted at obtaining energy. Although the natural history of the puddling phenomenon in herbivorous arthropods becomes better known, it is still largely unclear how puddling (in particular for sodium) affects fitness despite the growing knowledge of insect physiology at the cellular level. If we follow the definition used for puddling in Lepidoptera, representatives of a wide range of herbivorous and detrivorous terrestrial arthropods (Lepidoptera, Orthoptera, Blattodea, Hymenoptera, Hemiptera, Diptera, and Diplopoda) have been observed to puddle. It appears that those species with diets low in sodium (e.g., folivorous larvae) puddle for sodium whereas those with diets low in nitrogen (e.g., detritivores) puddle for nitrogen. Sex differentials in puddling behavior can usually be explained by transfers of nutrients from males to females during mating. Puddling is rare or absent in immature stages and there is some evidence that nutrients from puddles increase female reproductive success. Strong evidence for the widely cited hypothesis that sodium from puddles is used to enhance neuromuscular activity is still lacking. High mobility and long life spans could be associated with puddling behavior, whereas insects that are concealed or well defended are less likely to puddle (e.g., beetles). The role that risks of pathogen and parasite infection as well as predation at puddling substrates may play in the evolution of puddling remains virtually unexplored.     

冰冻切片技术在铁皮石斛显微结构上的应用

为了快速高效的观察兰科植物铁皮石斛的显微结构,利用光镜和改进的蔗糖保护--液氮速冻冰冻切片法,观察铁皮石斛根、茎、叶的显微结构。该技术方法是将铁皮石斛器官经过蔗糖磷酸缓冲液保护液处理后抽真空,再经过液氮速冻、包埋、切片、展片观察、染色以及拍照等步骤,制作出铁皮石斛根、茎和叶较完整的显微结构切片。研究结果表明,适合铁皮石斛根的最适条件为:蔗糖质量体积分数为8%、冷凝温度-25℃、切片厚度20μm;茎的最适条件为:蔗糖质量体积分数为16%、冷凝温度-20℃、切片厚度15μm;叶的最适条件为:蔗糖质量体积分数为4%、冷凝温度-20℃、切片厚度10μm。该研究在兰科植物显微结构观察和组织化学研究中将具有广阔的应用前景。     

后腹腔镜下肾部分切除术对肾癌患者肾功能和预后的影响

目的:探讨后腹腔镜下肾部分切除术对肾癌患者肾功能以及近远期预后的影响。方法:回顾性分析2012年1月～2017年8月在我院接受手术治疗的肾癌患者92例,根据不同手术治疗方法分为观察组(n=48)和对照组(n=44)。对照组行传统开放手术治疗,观察组行后腹腔镜下肾部分切除术。对比两组患者术前、术后血清肌酐(Cr)、血尿素氮(BUN)、β2-微球蛋白(β2-MG)、C反应蛋白(CRP)、白细胞介素-6(IL-6)水平的变化,术后1年、3年、5年生存率及切口感染、肺部感染、腹部疼痛、肾周血肿等并发症的发生情况。结果:观组患者手术时间、术后胃肠功能恢复时间、住院时间均明显短于对照组(P0.05),术中出血量、术后引流管引流量均显著低于对照组(P0.05)。术后1个月、术后2个月,两组患者血清Cr、BUN、β2-MG表达水平均较治疗前上升,且观察组以上指标显著低于对照组(P0.05)。术后,两组患者血清CRP、IL-6水平虽有升高,但观察组以上指标明显低于对照组(P0.05)。两组患者术后3年、5年的生存率均较术前下降,但观察组均分别高于对照组(P0.05)。术后,两组患者均有出现切口感染、肺部感染、腹部疼痛、肾周血肿等并发症,观察组总发生率(10.42%)明显低于对照组(29.54%,P0.05)。结论:后腹腔镜下肾部分切除术治疗肾癌患者可缩短患者的住院时间,对肾功能影响小,明显提高患者术后3年、5年生存率,且安全性更高。     

FlashPack: Fast and Simple Preparation of Ultrahigh-performance Capillary Columns for LC-MS*

1. Download : Download high-res image (99KB)
2. Download : Download full-size image

Highlights

• •Fast and simple capillary column packing protocol.
• •Low-pressure packing at <100 bars from ultrahigh sorbent suspension concentration.
• •Sorbent particle aggregation leading to blocking of the column entrance is avoided.
• •Effective for long capillary UHPLC column packing with a wide range of sorbents.

     

Refilling Nitrogen to Oxygen Vacancies in Ultrafine Tungsten Oxide Clusters for Superior Lithium Storage

Morphological engineering of nanosized transitional metal oxides shows great promise for performance improvement, yet limited efforts have been attempted to engineer the atomic structure. Oxygen vacancy (V_O) can boost charge transfer leading to enhanced performance; yet excessive V_O may impair the conductivity. Herein, tungsten oxide is atomically tailored by incorporating nitrogen heteroatoms into the oxygen vacancies. The efficient nitrogen‐filling into the oxygen vacancies is evidenced by the electron paramagnetic resonance spectroscopy and X‐ray absorption spectroscopy. The coordinated N atoms play a crucial role in facilitating the charge transfer and maintaining efficient lithium‐ion diffusion. Consequently, the tungsten oxide with N‐filled oxygen vacancies exhibits superior lithium‐ion storage performance.     

反硝化基因工程菌株YP4S的构建及对污水除氮特性研究

从养殖场污泥中筛选出菌株YP4,经16S rDNA分子发育树的同源序列比对,确定为克雷伯什菌属(Klebsiella sp.)。由NCBI数据库查编码亚硝酸还原酶(Nir)的基因nirS序列,设计引物,以铜绿假单胞菌PAOI基因组DNA为模板,应用PCR技术扩增目的片段nirS,经过双酶切、克隆和转化,得到重组质粒pYP4S,然后转化野生菌株YP4,构建反硝化基因工程菌YP4S。菌株生长曲线测定表明,工程菌株YP4S与YP4的生长特性基本一致。工程菌株YP4S对模拟污水COD、TN、NH_4^+-N和NO_3^--N具有较高的去除率,YP4S与YP4相比,对NO_2^--N积累的减少量为(32.44±3.96)%,明显减少了NO_2^--N的积累。通过正交试验获得工程菌株YP4S在C/N=10、T=30℃、r=200 r/min和pH=7.0的最佳组合条件下,对模拟污水TN去除率较高。应用工程菌株YP4S处理猪场沉淀池的实际污水,COD、TN、TP、NH_4^+-N和NO_3^--N去除率分别为(95.87±0.82)%、(76.38±3.84)%、(97.13±0.54)%和(75.35±2.57)%,NO_2^--N积累量为(3.31±1.24) mg/L,表明工程菌株YP4S具有较好反硝化作用,对含氮量高的实际污水修复具有潜在的应用前景。