波兰喀尔巴阡山麓漂白淋溶土中铁锰结核的分布、形态和化学组成研究

Iron and manganese oxides are common components of soils. They frequently occur in nodules constituting important soil sorbents and play a crucial role in a number of chemical reactions in the soil environment. In addition, the oxides are very sensitive to environmental changes (moisture, pH, Eh) constituting important indicators of soil-forming processes and water movement in the landscape. The objectives of the study were: i) to examine the distribution and size of Fe-Mn nodules in Albeluvisols containing a fragipan horizon; ii) to determine the morphology and chemical composition of the nodules, and iii) to estimate the effect of the fragipan horizon on water movement within the soil profile. An investigation was carried out on five soil profiles containing a fragipan horizon and classified as Fragic Albeluvisols within the Carpathian Foothills in Poland. In the Albeluvisols studied, the maximum concentration of Fe-Mn nodules occurred in the horizon lying directly on the fragipan horizon. This suggests that the pan acts as a natural barrier restricting water infiltration and leads to the seasonal development of a perched water table promoting redox processes. The most common are coarse (1--0.5 mm) and medium (0.5--0.25 mm) irregular Fe-Mn nodules showing a gradual boundary and undifferentiated internal fabric. Eluvial horizons contained also larger amounts of round and dense nodules with a sharp boundary, suggesting frequent oxidation and reduction. The fragipan horizon contained mainly irregular and soft nodules, suggesting longer saturation with water during the year. Concentrations of trace elements (Cu, Zn) and P were higher within Fe-Mn nodules than in the surrounding soil materials, showing that iron and manganese oxides adsorbed and immobilised these elements.     

Mesoscale eddies modulate the dynamics of human fishing activities in the global midlatitude ocean

Frequent fishing activities are causing overfishing, destroying the habitat of marine life, and threatening global marine biodiversity. Understanding the dynamics of fishing activities and their drivers is crucial for designing and implementing effective ocean management. The fishing activities in the open sea are reported to be characterized by high spatial variability in local waters; however, it is still unclear whether their high spatial variability is random or regulated by oceanographic variations. Mesoscale eddies are ubiquitous swirling currents that dominate locally biogeochemical processes. Previous case studies presented an ongoing debate regarding how eddies exert impacts on high trophic organisms, which imposes limitations on understanding the dynamics of fishing activities based on the bottom-top control hypothesis from eddies to fish and fishing activities. By combining global fishing activities from deep learning and oceanic eddy atlases from satellite monitoring, we showed that the spatial variations in fishing activities were closely related to mesoscale eddies in the global midlatitude ocean, confirming that fishing activities primarily targeting tuna, were aggregated in (repelled from) anticyclonic (cyclonic) eddy cores. This eddy-fishing activity relationship was opposite to satellite-observed primary production but corresponded well with the temperature and oxygen content in deeper water. By integrating existing evidence, we attribute eddy-related fishing activities to a reasonable hypothesis that warm and oxygen-rich deeper water in anticyclonic eddies relieves the thermal and anoxic constraints for diving predation by tuna while the constraints are aggravated in cold and oxygen-poor cyclonic eddies.     

Pollinators of the invasive plant, yellow starthistle (Centaurea solstitialis), in north-eastern Oregon, USA

The potential pollinators of yellow starthistle ( Centaurea solstitialis ) were surveyed at six sites in north-eastern Oregon, USA, between May and September from 2000 to 2002. The objective of the study was to determine the species composition and relative abundance of the insects that visited yellow starthistle throughout the flowering season and to assess the pollen loads on their bodies in order to infer which species might be the most effective pollinators of this invasive plant species in north-eastern Oregon. A total of 1923 individual flower visitors were collected at the six sites over the 3 year study period, comprising four orders, 41 families, and 203 species of insects. The 20 most commonly collected species represented nearly 59% of the individuals and just ten of these species could be considered the key pollinators, judging by the combination of abundance and pollen carriage (the megachilids, Megachile apicalis (introduced) and Megachile perihirta , the apids, Apis mellifera (introduced), Bombus bifarius , Bombus centralis , Svastra obliqua , and Melissodes lutalenta , the halictids, Halictus tripartitus and Halictus ligatus , and the tachinid, Peleteria malleola . Over the 3 year study period, the six sites were consistently distinct in their flower visitor fauna, with the metropolitan Pendleton sites having a species composition distinct from the four mountain sites. Consistent patterns of interannual variation also were observed over the 3 year study. These patterns of flower visitation are interpreted in the context of the plant community within which yellow starthistle grows in north-eastern Oregon.     

中华鲟硬组织微结构及微化学的特征探索

为了在中华鲟洄游生态学研究上有新突破,实验首次比较研究了中华鲟3种硬组织(耳石、背骨板和胸鳍条)的微结构和微化学特征.结果 发现,耳石结构松散,存在多个耳砂(微晶球霰石球晶)颗粒,且每个颗粒均具有独立的核心;背骨板存在分层现象;胸鳍条结构较为致密,且均一.胸鳍条、耳石中生境元素Co/Ca、Sr/Ca和Ba/Ca比特征变...     

鲤疱疹病毒Ⅱ型对异育银鲫背鳍细胞的显微形态与免疫基因表达水平的影响

为研究鲤疱疹病毒Ⅱ型(Cy HV-2)体外感染复制特征以及异育银鲫抗病毒免疫应答反应。本实验采用组织块培养法建立了异育银鲫背鳍细胞的原代培养体系。结果显示,在10 d左右可观察到组织块迁移分离出新的单层细胞,3周左右细胞可覆盖底部面积为25cm2培养瓶的底部;经Cy HV-2悬液感染离体培养的原代细胞,3 d后病毒滴度增殖至106拷贝/m L;在病毒感染6 d后出现典型的细胞病变效应;Cy HV-2感染原代细胞后,分析前期通过鱼体水平实验鉴定出的与该病毒感染相关的免疫基因:PNP5a、MPO、MHCⅠ、LYZ-C、IL-11、ITLN、PNP5a和DUSP,Real-time Rt-PCR结果显示大部分基因在细胞水平均有显著性的上调,与鱼体水平实验结果一致。本研究建立了原代培养的异育银鲫背鳍细胞,用于构建体外感染Cy HV-2病毒的细胞模型,为深入研究Cy HV-2的感染复制规律及其与宿主的相互作用关系,以及细胞水平筛选抗病毒药物实验奠定了基础。     

雌激素受体与M2mAchR在成年雌兔背根神经节中的共存

为检测成年雌兔背根神经节中是否存在雌激素受体(ER)与M2型乙酰胆碱受体(M2mAchR)的分布与共存,采用免疫荧光双标记染色法对ER与M2mAchR在背根神经节中的分布情况进行了研究。结果显示,在成年雌兔背根神经节中:(1) ER分布主要以神经元为主。其中,ERα主要表达于中小型神经元,而ERβ则多分布于大中型神经元。(2)相较ER而言,M2mAchR分布更为广泛,除神经元外,神经纤维等组织上也有弱阳性表达。(3)两种ER与M2mAchR均有共存现象,但共存情况存在差异,ERα/M2mAchR主要共分布于中小型细胞,ERβ/M2mAchR主要共分布于大中型神经元。结果表明,首先,雌激素具有通过影响背根神经节部分神经元的活动而实现对躯体内脏感觉活动间接调节的条件。其次,在此影响的机制中,雌激素除可以直接作用于神经元上的受体之外,还具有与共表达的M2mAchR交互作用而实现的条件。为研究雌激素影响神经系统调控活动的机制以及背根神经节的神经内分泌调节机制提供了重要的形态学依据。     

Minimally invasive approach to lumbosacral decompression in a cadaveric canine model

AIMS: To determine efficacy of a minimally invasive (MI) surgical approach using a human MI lumbar retractor for canine lumbosacral dorsal laminectomy and partial discectomy and to compare this technique to the standard open surgical (OS) approach.

METHODS: Lumbosacral dorsal laminectomy and partial discectomy was performed on 16 large-breed canine cadavers using either a standard OS (n=8) or MI (n=8) approach. Skin and fascial incision length, procedure time, and intraoperative complications were recorded. Postoperatively specimens were evaluated for laminectomy and discectomy dimensions, and visible damage to the cauda equina and exiting nerve roots.

RESULTS: Median length of skin and fascial incisions in the OS group were longer than in the MI group (p<0.001). Median laminectomy length was similar between both approaches (p=0.234) but width was greater for the MI than OS approach (p=0.002). Both approaches achieved similar partial discectomy width (p=0.279). Overall surgical time was longer for MI approaches compared to OS, with a median of 18.5 (min 15.5, max 21.8) minutes for MI compared to 14.6 (min 13.1, max 16.9) minutes for OS (p=0.001).

CONCLUSIONS: The MI approach reduced incision lengths while retaining comparable laminectomy and discectomy dimensions. For this in vitro model the MI approach required more time to complete, but this difference may not be relevant in clinical cases.

CLINICAL RELEVANCE: Dogs undergoing lumbosacral dorsal laminectomy are commonly large-breed dogs. The traditional open approach requires a large skin incision and soft tissue dissection, especially in overweight animals. A MI approach accomplishing the same surgical result while minimising soft tissue trauma could reduce post-operative pain and recovery time, and may lower wound-related complications. Clinical studies are needed to confirm postoperative benefit and assess operating times in vivo.     

Surgical resection of an osteoma of two thoracic spinous processes in a horse

This report describes the successful surgical removal of an osteoma of the thoracic dorsal spinous processes of a horse that presented with back pain. Osteomas of the spine are frequently reported in the literature in people, but have not been previously described in the horse.     

Description of a regional anaesthesia technique for the dorsal cranium in the dog: a cadaveric study

Objective

To identify landmarks and to describe a technique for nerve blockade of the dorsal cranium in dogs.