Effects of land preparation and maize cultivar on efficiency of N-fertilizer applied at different times and by different methods in maize—mungbean association using15N

Summary A field experiment was conducted using¹⁵N-labelled urea on a Reddish Brown Lateritic (Peleustult) soil. Growing two crops on flat land and on soil ridges of 15 cm height produced similar comparative effects from fertilizer on maize. However, fertilizer applied by broadcasting on maize with a 50 cm effective band followed by incorporating was more useful to mungbean than that applied by banding below the cereal seed rows when crops were grown on flat land. The reverse was observed when crops were grown on ridges. It was deduced that the maize cultivar was not likely to affect comparative efficiencies of fertilizer. For fertilizer application at sowing, broadcasting in 50 cm maize effective band followed by incorporating was slightly superior to banding below maize seed rows. Side-dressing of fertilizer to maize at 4 weeks after sowing was superior to application at sowing. Evenly-split application, at sowing and at 4 weeks after sowing, was either only slightly superior or comparable to non-split application by banding below maize seed rows at sowing, depending on placement method of the first application. Soil moisture status as a possible factor rendering discrepancy in the comparative efficiencies obtained by different authors is discussed.     

Conditions for a high plating efficiency of free cell suspensions of Haplopappus gracilis (Nutt) gray

Summary Suspensions of Haplopappus gracilis cells, containing about 80% free cells, were obt ained from log-phase cultures by filtration through 3 nylon sieves having decreasing mesh widths from 297, 210 and 88 m. From the free cell suspensions, 75 to 90% of the cells developed into visible colonies when the plating procedure was divided into two steps: a) plating the cells at high concentration in soft agar on feeder agar; b) replating the resulting aggregations at appropriate concentrations on fresh feeder agar. From the results, it is inferred that, in the replating step, the volume of the inoculum is the deciding factor which influences the resulting plating efficiency.     

Effect of food limitation on food consumption and reproductive allocation by adult milkweed bugs, Oncopeltus fasciatus

Male/female pairs of adult milkweed bugs, Oncopeltus faciatus were offered reduced food rations (100 mg milkweed seeds/week, 50 mg seeds/week, and 25 mg seeds/week) at 232C, 14L : 10D photoperiod. The high rate of food consumption normally occurring during the teneral period (first 8 days posteclosion) and subsequent food consumption were reduced on both reduced rations. Initial fresh weight was lost by bugs on both reduced rations and their weekly fresh body weight tended to remain less than bugs on the 100 mg seeds/week ration.Normal onset of egg production (about 3 weeks posteclosion) was delayed 6 weeks and normal length of a female's life (13–14 weeks) was increased 7–8 weeks on the 25 mg seeds/week ration. Rate of egg production exhibited a linear decrease with decrease in food ration on both reduced rations due to an increased interclutch interval, while fresh egg weight, duration of egg stage, number of eggs/clutch and percentage of clutches containing fertile eggs were little affected.Gross egg production efficiency (efficiency of conversion of ingested food into eggs = dry mg egg production × 100/dry mg food ingested) was high on both the 100 and 50 mg seeds/week rations (27.9% and 21.1%, respectively) and low (7.7%) on the 25 mg seeds/week ration. These data are discussed in the context of the reciprocal interaction between nutrient intake and egg production.     

动物基因组编辑中提升CRISPR/Cas9介导的同源重组效率研究进展*

基因组编辑技术可以对DNA或RNA进行精准改造,极大地促进了生命科学的发展。CRISPR/Cas9系统在靶位点诱导DNA发生双链或单链损伤,细胞对损伤部位采用无供体模板的非同源末端连接(non-homologous end joining,NHEJ)或有供体模板的同源重组(homologous recombination,HR)修复。基于HR的基因组编辑策略通常被用于获得DNA的精准改造,而NHEJ在动物DNA损伤修复中起主导作用。为了提升HR效率,研究人员设计了多种方案,包括CRISPR/Cas9系统优化和DNA修复通路调控等。从DNA损伤修复途径、Cas9变体选择、sgRNA设计、供体模板设计、DNA修复途径相关蛋白功能调控、供体模板募集效率提升、细胞周期调控及编辑细胞生存效率提升等方面详细综述了相关研究成果,发现尚未开发出放之四海而皆准的HR提升策略,基于HR的基因组编辑需要针对具体案例制定个体化策略。旨在为动物基因组编辑中提升CRISPR/Cas9介导的HR效率研究提供理论参考,为动物基因功能分析、基因治疗和经济动物基因编辑育种提供帮助。     

CO2倍增对不同基因型大豆光合色素含量和荧光诱导动力学参数的影响

研究了CO_2倍增对大豆(Glycine max L.)Bragg(野生型)及其不同单基因突变品系Nts 382(超结瘤突变体)和Nod 49(不结瘤突变体)某些光合特性的影响。结果表明,CO_2倍增能提高Bragg、Nts 382和Nod 49的叶绿素(Chl)和类胡萝卜素(Car)的含量,但不同品系提高的幅度有所不同。荧光诱导动力学测定结果表明,CO_2倍增均能提高其PSⅡ活性、PSⅡ原初光能转化效率和光合作用潜在量子转化效率。CO_2倍增更有利于提高Nts 382的荧光光化学猝灭系数(qp)和PSⅡ总的光化学量子产量,以及较大幅度地降低荧光非光化学猝灭系数(qN),有助于把所捕获的光能用于进行光合作用。这可能与Nts 382是超结瘤突变体,比Bragg和Nod 49能更充分地利用空气中的氮素有关。     

Utilization of milk energy by suckling mink kits

A total of 36 mink dams and their litters of 3, 6 or 9 kits were used for determination of milk intake of the suckling young by means of deuterium dilution technique, and chemical composition of milk and of kit bodies. Measurements were performed during lactation weeks 1?–?4, each week with 3 dams with each litter size. Milk intake was determined over a 48?h measurement period, and by the end of this milk samples were collected and 2 kits (litters of 6 and 9) or 1 kit per litter (litters of 3) were killed for body chemical composition. Based on the results, different models were applied for calculation of the energetic efficiency of milk. Dam milk yield increased steadily from week 1 until week 3 but only slightly from week 3 to 4. The increase declined with increasing litter size, and for dams suckling 9 kits the increment from week 3 to week 4 was only 2?g. The dry matter content of milk increased significantly as lactation progressed, being reflected in crude protein increasing from 6.9% in lactation week 1 to 8.1% in week 4. Milk fat increased concomitantly from 5.6% to 8.0%. In kit bodies, crude protein content increased from 9.4% in week 1 to about 12% in weeks 3 and 4. Body fat content increased from week 1 (4.1%) to week 3 (8.4%) and then declined in week 4 (7.1%). Animals suckled in litters of 3 kits had the highest milk intake and live weight and kits suckled in litters of 9 had the lowest milk intake, live weight and daily gain. In terms of milk intake per g gain kits in litters of 6 were the most efficient, with 4.1?g milk per g body gain. The metabolizable energy requirement for maintenance (MEm) was estimated to 448 kJ/kg^0.75 and the efficiency of utilization of ME for body gain (k_g) to 0.67, the estimates being higher (MEm) or in good agreement with previous findings (k_g) in suckling mink kits.     

Repercusión de un sistema centralizado de ingresos sobre la eficacia y eficiencia de una unidad geriátrica de recuperación funcional

ObjectiveTo evaluate the influence of a change in the management of admissions on the activity and care outcomes of a Geriatric Functional Recovery Unit (GFRU).Material and methodsA retrospective observational study was conducted. Since 2000, the Hospital Central Cruz Roja GFRU has been collecting data grouped into periods of 4 years, except for the centralised admissions (September 2016-December 2018). The data collected on admission included the Red Cross Functional and Mental scales, the Barthel index, the main diagnosis of the functional decline (grouped into stroke, orthopaedic problem, and multifactorial immobility episodes), and comorbidity evaluated by the Charlson index. The following outcome variables were analysed: the overall and relative functional gain at discharge; length of hospital stay; the functional efficiency, discharges to nursing homes, and transfers to acute care units. An analysis was made of the relationship between the admissions from the centralised unit and the previous period (directly admission managed by GFRU), using multivariate analysis (linear regression for continuous outcome variables and logistic regression for the dichotomous ones), adjusted for admission variables.ResultsPatients admitted from the centralised unit showed a greater overall and relative functional gain (difference between both means: 3.49 points, 95% CI; 1.65-5.33, and 12.41%, 95% CI; 0.74-24.08, respectively), longer stay (12.92 days, 95% CI; 11.54-14.30) and lower efficiency (−0.36, 95% CI; −0.16 to −0.57), higher risk of institutionalisation (OR 1.61, 95% CI; 1.19-2.16), and transfers to acute care units (OR 3.16, 95% CI; 2.24-4.47).ConclusionsA centralised admissions system had an influence on the improvement of functional parameters in the patients, but with a longer length of hospital stay, and lower efficiency. Increases in institutionalisation at discharge and transfers to acute care units were also observed.     

Surface modification via wet chemical etching of single-crystalline silicon for photovoltaic application

The potential of solar cells have not been fully tapped due to the lack of energy conversion efficiency. There are three important mechanisms in producing high efficiency cells to harvest solar energy; reduction of light reflectance, enhancement of light trapping in the cell and increment of light absorption. The current work represent studies conducted in surface modification of single-crystalline silicon solar cells using wet chemical etching techniques. Two etching types are applied; alkaline etching (KOH:IPA:DI) and acidic etching (HF:HNO₃:DI). The alkaline solution resulted in anisotropic profile that leads to the formation of inverted pyramids. While acidic solution formed circular craters along the front surface of silicon wafer. This surface modification will leads to the reduction of light reflectance via texturizing the surface and thereby increases the short circuit current and conversion rate of the solar cells.