EFFECT OF CONTRAST MEDIUM INJECTION DURATION ON PEAK ENHANCEMENT AND TIME TO PEAK ENHANCEMENT OF CANINE PULMONARY ARTERIES

Our goal was to investigate the effect of contrast medium injection duration on pulmonary artery peak enhancement and time to peak enhancement. Fourteen dogs were allocated into one of seven predefined weight categories, each category contained two dogs. Dogs in each weight category were assigned to group A or B. Animals in each group received a different contrast medium injection protocol. In group A, a fixed injection rate of 5 ml/s was used. In group B, the contrast injection rate was calculated as follows: flow rate=contrast volume/scan duration+10 s. Time to peak enhancement and peak enhancement of the main left and right pulmonary arteries were measured on single‐level, dynamic CT images for a fixed time of 30 s. Rank correlation (Spearman's) coefficients between injection duration and time to peak enhancement and between body weight and peak enhancement were calculated. For group A, there was a significant negative correlation between peak enhancement and weight (r=?0.94; P=0.005), while for group B, there was no significant correlation (r=?0.64 and P=0.18). There was a significant correlation between time to peak enhancement and injection duration in both groups (group A: r=0.99; P=0.006 and group B: r=0.85; P=0.02). In conclusion, injection duration is a key feature in a CT angiography injection protocol. A protocol with an injection duration adjusted to the scan duration seems to be particularly suitable for veterinary applications where a population with great weight variability is studied.     

Nutrient flows and land use change in a rural catchment: a modelling approach

Due largely to unprecedented land-use changes in the Porijõgi River catchment (southern Estonia) losses of nutrients and organic matter have decreased significantly. During the period 1987–1997 abandoned lands increased from 1.7 to 10.5% and arable lands decreased from 41.8 to 23.9%. At the same time, the runoff of total-N, total-P, SO₄ and organic matter (after BOD₅) decreased from 25.9 to 5.1, 0.32 to 0.13, 78 to 48, and 7.4 to 3.5 kg ha^–1 yr^–1, respectively. The most significant decreases occurred in agricultural subcatchments while the changes were insignificant in the forested upper course catchment. A simple empirical model which incorporates land-use pattern, fertilization intensity, soil parameters and water discharge accurately described the variations of total-N and total-P runoff in both the whole catchment and its agricultural subcatchments (R ² varies from 0.95–0.99 for N to 0.49–0.93 for P). In small agricultural subcatchments the rate of fertilization is found the most important factor for nitrogen runoff, whereas in larger mosaic watersheds land use pattern plays the main role. Seven alternative scenarios compiled on the base of the empirical model allow to forecast potential nitrogen and phosphorus losses from the catchment. This information can be used in further landscape and regional planning of the whole region.     

柑橘园植保无人飞机低容量喷雾技术探索——以柑橘木虱和潜叶蛾防控为例

【目的】探索植保无人飞机(unmanned aerial vehicle,UAV)喷雾在柑橘冠层的雾滴沉积分布规律和无人机植保作业参数,并开展柑橘木虱(Diaphorina citri)和潜叶蛾(Phyllocnistis citrella)无人飞机防控实效研究,评估防治效果、作业效率和综合效益,为UAV低空低容量喷雾技术的建立和在柑橘产区的应用提供依据。【方法】在丰产期的鸡尾葡萄柚园,将4行约100株自然圆头形树冠修剪成开心形,另选4行自然圆头形树冠作为对照。在采样植株冠层内部搭设立体网格架,网格架垂直方向分上、中、下3层,每层设置3×5共计15个采样点,每株树共计45个观察点,每个点放置两张4 cm×6 cm铜版纸卡作为雾滴承接载体。以0.5%诱惑红水溶液作为示踪剂,六旋翼UAV分别在不同飞行作业速度(v₁=0.7 m·s^-1、v₂=1.2 m·s^-1、v₃=1.7 m·s^-1)和不同作业高度(h₁=1.0 m、h₂     

Assessment of the posterior segment of the cat eye by optical coherence tomography (OCT)

OBJECTIVES: To assess the feasibility of optical coherence tomography (OCT) for examining the cat ocular fundus, to provide normative data on retinal thickness in different fundus regions, and to demonstrate selected surgically induced vitreoretinal pathologies in the cat. ANIMAL STUDIED: Forty-five eyes of 28 healthy domestic cats and two eyes of domestic cats that had undergone subretinal implantation surgery for a visual prosthesis were examined. PROCEDURES: An optical coherence tomograph (Zeiss-Humphrey) was used to examine the anesthetized animals. At least five vertical and five horizontal scans in regular distribution were recorded for each cat including (1) the peripapillary region, (2) the area centralis, and (3) the peripheral retina. Thickness was measured manually at five locations in each scan. Retinal thickness was compared in the three above-mentioned fundus regions, between eyes and between vertical and horizontal scans. OCT was additionally performed in animals with retinal detachment and a subretinal visual prosthesis. RESULTS: OCT measurements required only minimal adjustments of human settings and yielded high quality images. In comparison to humans intraretinal layers were more difficult to differentiate. Retinal thickness was highest in the peripapillary region (245 +/- 21 microm), followed by the peripheral retina (204 +/- 11 microm) and the area centralis (182 +/- 11 microm; all P < 0.0001). There was no statistically significant difference between right and left eye or between vertical and horizontal scans. OCT demonstrated retinal detachment, an iatrogenic break and a subretinal prosthetic device in high detail. CONCLUSIONS: Retinal thickness was measurable with high precision; values compare well to older histologic studies. OCT bears significant advantages over histology in enabling one to repeat measurements in living animals and thus allowing longitudinal studies. Various vitreoretinal pathologies common in feline eyes are detectable and quantifiable by OCT.     

高效液相色谱法测定乳与乳制品中柚皮苷

建立高效液相色谱法测定乳与乳制品中柚皮苷含量的方法。样品用甲醇提取,在284 nm波长下,流动相为体积分数0.1%醋酸水溶液-乙腈（75∶25,V/V）,C18色谱柱分离,经二极管阵列检测器检测,外标法定量。结果表明：柚皮苷在5～500 μg/mL质量浓度范围内线性关系良好,相关系数为0.999 9;分别向乳粉、液态乳和酸乳样品中在加入柚皮苷标准品0.02、0.04、0.08 g/100 g时,加标回收率分别为96.2%～103.2%、96.3%～103.7%和99.7%～104.1%,相对标准偏差分别为1.12%～2.31%、1.25%～1.85%和1.24%～1.66%。该检测方法简便、快速、准确、重复性好,能够测定乳与乳制品中柚皮苷的含量。     

INTERACTIVE EFFECTS OF SALINITY AND N ON PEPPER (CAPSICUM ANNUUM L.) YIELD,WATER USE EFFICIENCY AND ROOT ZONE AND DRAINAGE SALINITY

The aim of this study was to determine the salt tolerance of pepper (Capsicum annuum L.) under greenhouse conditions and to examine the interactive effects of salinity and nitrogen (N) fertilizer levels on yield. The present study shows the effects of optimal and suboptimal N fertilizer levels (270 kg ha^?1 and 135 kg ha^?1) in combination with five different irrigation waters of varying electrical conductivity (EC) (EC_iw = 0.25, 1.0, 1.5, 2.0, 4.0, and 6.0 dS m^?1) and three replicates per treatment. At optimal N level, yield decreased when the irrigation water salinity was above EC_iw 2 dS m^?1. At the suboptimal N level, a significant decrease in yield occurred only above EC_iw 4 dS m^?1. At high salinity levels the salinity stress was dominant with respect to yield and response was similar for both N levels. Based on the results it can also be concluded that under saline conditions (higher than threshold salinity for a given crop) there is a lesser need for N fertilization relative to the optimal levels established in the absence of other significant stresses.     

制干辣椒果实辣椒素对干旱、盐及其双重胁迫的响应

为明确干旱、盐等环境因素对制干椒辣椒素含量的影响,试验以红龙23号板椒为材料,从现蕾期开始设置不同土壤含水量65%(W1)、45%(W2)和NaCl(S1=120 mmol·L^-1)及盐旱复合处理(W1S1、W2S1),利用高效液相色谱法分析转色期果实辣椒素素含量,并送样进行转录组测序。结果表明,W1处理下辣椒素含量较对照增加107.11%,W2处理时辣椒素含量下降73.01%;含盐处理均能提高辣椒素含量,其中W2S1处理的较对照高392%。盐、旱胁迫主要影响苯丙烷生物合成途径,其中HCT、4CL、CAD等基因表达受影响较大;聚类分析表明BCKDHE2、ENRb等基因主要响应干旱胁迫,CCR、GS2主要响应盐胁迫。由上可知,适度干旱和盐胁迫均能提高辣椒素含量;干旱加剧时与盐分的复合效应更显著,对辣椒素积累的促进作用更大。     

Driving factors of direct greenhouse gas emissions from China’s pig industry from 1976 to 2016

Livestock cultivation is a significant source of greenhouse gas (GHG) emissions, accounting for 14.5% of the total anthropogenic emissions. China is responsible for a considerable share of the global livestock emissions, particularly caused by pork production. We used the Kaya identity and the logarithmic mean Divisia index (LMDI) to decompose the national annual GHG emissions from enteric fermentation and manure management in pig farming in China from 1976 to 2016. We decomposed the sources of the emissions into five driving factors: (1) technological progress (e.g., feed improvement); (2) structural adjustment in the livestock sector; (3) structural adjustment in agriculture; (4) affluence; and (5) population growth. The results showed that the net GHG emissions from the pig sector in China increased 16 million tons (Mt) of carbon dioxide equivalents (CO₂eq) during the study period. The decomposition analysis revealed that structural adjustment in agriculture, growing affluence, and population growth contributed to an increase of the GHG emissions of pork production by 23, 41, and 13 Mt CO₂eq, respectively. The technological progress and structural changes in animal husbandry mitigated emissions by –51 and –11 Mt CO₂eq, respectively. Further technological progress in pig production and optimizing the economic structures are critical for further reducing GHG emissions in China’s pig industry. Our results highlight the dominant role of technological changes for emission reductions in the pig farming.