Mercury accumulation in the squirrel monkey eye after mercury vapour exposure

Squirrel monkeys were exposed to mercury vapour at different concentrations and for different numbers of days. The calculated total mercury absorption ranged between 1.4-2.9 mg (range of daily absorption 0.02-0.04 mg). The monkeys were killed at different intervals after the end of exposure (range 1 month - 3 years) and the eyes were enucleated. Eyes from four un-exposed monkeys were used as control material. Mapping of the mercury distribution in the eye revealed that the non-myelin-containing portion of the optic disc was densely loaded with mercury deposits, which are mostly confined to the capillary walls and the glial columns. The white matter of the brain does not accumulate mercury at these exposure levels, which might suggest that the myelinization process inhibits the accumulation of mercury. The pigmented epithelium of the pars plicata of the ciliary body and of the retina contained a considerable amount of mercury. This finding indicates that mercury is trapped within the melanocytes, which keeps potentially dangerous material from reaching the neural retina. In addition, the retinal capillary walls were densely loaded with mercury deposits, even 3 years after exposure. It was also found that the inner layers of the retina accumulated mercury during a 3-year period. It is known that the biological half-time of mercury in the brain may exceed years. This seems also to be the case for the ocular tissue.     

Mercury levels in freshwater fish of the state of South Carolina

Samples of fish from freshwater sources of rivers, lakes and ponds all over the state of South Carolina were collected during the Summer of 1974 and 1975. The fish collected were Bass, Bluegill, Redbreast, Catfish, Shad, Carp, Crappie, Mudfish and Pike. Samples were analyzed using the flameless atomic absorption procedure outlined by Hatch and Ott, and Uthe et al as modified for use with Perkin-Elmer, Coleman MAS-50 mercury analyzer. Triplicate samples of fish tissue were analyzed by wet digestion method. The mean mercury levels in ppb were determined for baseline mercury levels. A significant finding of this report is that those species for which fish of widely differing weights were analyzed, larger fish had higher mercury levels. Mercury levels exceeding the U.S. Food and Drug Administration guideline of 500 ppb for fish tissues have been found in the Mudfish from Edisto River and Pike fish from Lake Murray. Higher levels of mercury occurred in the highly vascularized blood tissues of liver and kidney than in muscle. Carnivorous and bottom-feeding fishes are the most reliable indicators of mercury pollution.     

新型脱汞试剂对铅锌冶炼制酸废水中汞的影响

为了实现高效率、低成本地提取铅锌冶炼烟气制酸废水中的汞,通过分析污酸中汞形态研究,开发了新型脱汞试剂,采用单因素试验方法在反应温度为25℃、反应时间25 min、脱汞剂/汞质量比为0.78、搅拌速率150 rpm/min的基础条件下研究了搅拌桨结构、不同原料浓度对反应的影响。实验结果表明:开发的脱汞剂选择性好、效率高、汞脱除率大于99.5%;渣含汞较高,为65.61%,处理后液汞浓度降至0.03 mg/L以下,实现达标排放;与硫化-沉淀法相比,该方法具有工艺流程短、操作简单等特点,并且该工艺对汞溶液的适应性广。     

Lead content of rice collected from various areas in the world

Rice samples consumed by local populations were collected between 1990 and 1995 in 17 areas in the world, mostly from Asia (10 areas), but also from 7 areas outside of Asia. In total, 1528 samples were obtained (about one half from Japan) and were analyzed for lead (Pb) by electrothermal atomic absorption spectrometry. When the Pb contents in rice samples were classified into 10 areas in Asia, the highest and the lowest geometric means (GMs) were for Indonesia (38 ng/g) and Australia (2 ng/g), respectively. Among 7 regions outside Asia, the GM was highest for Spain (58 ng/g) and the lowest for the USA. (3 ng/g). Moreover, inter-regional differences were significant, when more than 100 samples from one area were divided into 3-9 regions and GMs for regions were compared. There was a marked difference in Pb contents in rice by areas and regions in the world. Nevertheless, comparison by area of the present results with those reported in literature show that there has been no substantial reduction in Pb in rice in the past decade either in Japan or elsewhere in the world.     

Mercury in various tissues of fish caught downstream of a wood pulp factory in the kammerfoss river, South Norway

The mercury content of perch (Perca fluviatilis) and brown trout (Salmo trutta) from a river in South Norway, previously shown to be contaminated with mercury from a wood pulp factory, was studied during a 5-years period after the use of mercury in the factory had been discontinued in 1970. In addition to muscular tissue, samples of liver, kidney, brain, heart, and gonads were also analyzed in some cases. The mercury level in the musculature remained nearly constant at about 1 mug/g during the years 1971-1975. The organ distribution studies indicate a relatively even concentration level in different organs of moderately exposed individuals, while mercury contents exceeding 100 mug/g have been observed in the liver of fish exposed to high mercury pollution.     

Mercury in the bivalve Anadara (Senilia) senilis from Ghana and Nigeria

Samples of the bivalve Anadara (Senilia) senilis collected from a closed lagoon (Sakumo) and two open lagoons in Ghana (Benya and Ningo; n = 550), and the Bonny river estuary in Nigeria (n = 620), were analyzed for their total and organic mercury content. Total mercury concentration showed significant spatial differences, with median values of 0.1 microgram/g dry wt. in the closed lagoon, 0.2 in the estuary and 0.3 in the open lagoons. Concentration tended to be higher during the dry season in the lagoons, but lower in the estuary. The median relative organic concentration varied between 20 and 60% methyl Hg, depending on location and season. Age effects were detected in the lagoons, total Hg concentration decreasing with length.     

斜轧中凸棱斜率对轧件心部应力影响

应用ANSYS-DYNA有限元软件,对螺旋孔型斜轧轴类件进行轧制过程的模拟,得到轧件中间横截面的上应力分布曲线,同时分析了凸棱斜率对轧件中心部位应力变化的影响规律.结果认为,凸棱斜率对轧件中心部位主应力和等效应力有较大的影响,轧件心部的应力状态和积累是导致心部疏松的主要原因.     

红粉中三种价态汞测定的研究

试样用稀硝酸加高锰酸钾溶解，测定Hg、Hg22+和Hg2+总量，另取一份试样用稀硝酸溶解并定容后，取两份溶液，一份测定Hg2+；另一份用高锰酸钾氧化Hg22+为Hg2+，测定Hg22+、Hg2+含量，然后用差减法求出Hg、Hg22+和Hg2+的含量。本法操作简便，数据稳定、准确。     

Retinal anatomy of a new species of bresiliid shrimp from a hydrothermal vent field on the Mid-Atlantic Ridge

A new species of shrimp (Rimicaris sp.) was recently collected from the Snake Pit hydrothermal vent field on the Mid-Atlantic Ridge. Until the discovery in 1989 that the deep-sea, hydrothermal vent species, Rimicaris exoculata, possessed a hypertrophied dorsal eye, everyone believed that animals recovered from vent environments were blind. Like R. exoculata, Rimicaris sp., a small orange bresiliid shrimp, has an enlarged dorsal eye specialized for detecting light in a very dim environment instead of the expected compound eye. The individual lenses characteristic of a compound eye adapted for imaging have been replaced in Rimicaris sp. by a smooth cornea underlain by a massive array of photosensitive membrane. The number of ommatidia in this species is about the same as in shrimp species that live at the surface; however, the photoreceptors are larger in the deep-sea species and the shape of the photoreceptors is markedly different. The light-sensitive region of the photoreceptor is much larger than those of other shrimp and the rest of the receptor is much smaller than normal. All screening pigment has moved out of the path of incident light to a position below the retina, and the reflecting pigment cells have adapted to form a bright white diffusing screen between and behind the photoreceptors. The ultrastructure of the microvillar array comprising the rhabdom is typical for decapod crustaceans; however, there is a much greater volume density of rhabdom (80% to 85%) than normal. There is no ultrastructural evidence for cyclic rhabdom shedding or renewal. Rimicaris sp. has apparently adapted its visual system to detect the very dim light emitted from the throats of the black smoker chimneys around which it lives.     

Dieldrin in fish and shellfish from the Mersey Estuary and Liverpool Bay

OBJECT: The authors studied the reliability of a new method for noninvasive assessment of cerebral perfusion pressure (CPP) in head-injured patients in which mean arterial blood pressure (ABP) and transcranial Doppler middle cerebral artery mean and diastolic flow velocities are measured. METHODS: Cerebral perfusion pressure was estimated (eCPP) over periods of continuous monitoring (20 minutes-2 hours, 421 daily examinations) in 96 head-injured patients (Glasgow Coma Scale score < 13) who were admitted to the intensive care unit. All patients were sedated, paralyzed, and ventilated. The eCPP and the measured CPP (ABP minus intracranial pressure, measured using an intraparenchymal microsensor) were compared. The correlation between eCPP and measured CPP was r=0.73; p < 10(-6). In 71% of the examinations, the estimation error was less than 10 mm Hg and in 84% of the examinations, the error was less than 15 mm Hg. The method had a high positive predictive power (94%) for detecting low CPP (< 60 mm Hg). The eCPP also accurately reflected changes in measured CPP over time (r > 0.8; p < 0.001) in situations such as plateau and B waves of intracranial pressure, arterial hypotension, and refractory intracranial hypertension. A good correlation was found between the average measured CPP and eCPP when day-by-day variability was assessed in a group of 41 patients (r=0.71). CONCLUSIONS: Noninvasive estimation of CPP by using transcranial Doppler ultrasonography may be of value in situations in which monitoring relative changes in CPP is required without invasive measurement of intracranial pressure.     

硫化铵提硫过程中汞、银、锌的浸出行为研究

硫化锌矿采用加压浸出技术处理后,得到的浸出渣经浮选和热过滤能获得纯度较高的硫磺,但硫的回收率低,且其中有价金属不易综合利用。利用硫化铵从热过滤渣中进一步回收硫,并对提取硫磺过程中汞、银、锌的浸出行为进行研究,分析了(NH4)2S浓度、液固比和浸出时间对浸出过程的影响。研究表明,在常温,(NH4)2S浓度为1.0 mol/L,液固比为6:1,浸出时间为60min的条件下,元素硫浸出率为95.36%,Hg、Ag、Zn的浸出率分别为4.71%、33.73%、0.32%。采用蒸馏热分解多硫化铵浸出母液,元素硫回收率为95%,获得的元素硫纯度达到99.5%以上。     

Evaluation of the ESP Culture System II for recovery of mycobacteria from blood specimens collected in isolator tubes

The reliability of the ESP Culture System II (ESP II; AccuMed International, Westlake, Ohio), a continuously monitoring, nonradiometric mycobacterial culture system, for recovery of mycobacteria from sediments of blood collected in an Isolator tube was evaluated by comparing its performance to inoculation of the sediment onto Middlebrook 7H11/7H11 selective biplates. Of 1,704 blood specimens, 73 (4.3%) were positive for mycobacteria (68 Mycobacterium avium complex and 5 M. tuberculosis). Fifty-three specimens were positive by both methods; 13 were positive by ESP II only, and 7 were positive by Middlebrook agar only (chi square = 1.8; P > 0.05). The mean times to positivity were 15.6 days for ESP II and 19.0 days for Middlebrook agar (P < 0.01). The time to detection was the same for 13 specimens; ESP II was positive first for 33, and agar plates were positive first for 7. ESP II allowed recovery of more mycobacteria (90.4% of all isolates versus 82.2% for Middlebrook agar) from sediments of blood specimens collected in Isolator tubes, and it provided significantly faster detection than did Middlebrook plates.     

乱岩塘汞矿高压地下水防治研究

本文通过对乱岩塘汞矿开采时期高压地下水防治研究,在保证原有水系平衡的基础上,采用全断面帷幕注浆堵水技术,进行断层水的防治,并顺利通过断层,有效地回收矿产资源,取得了较好的经济效益。     

Strain and age effects on egg composition from hens fed diets rich in n-3 fatty acids

The objective of this study was to compare the analgesic effects of intra-articularly administered bupivacaine with bupivacaine/morphine during and after therapeutic knee arthroscopy. In a prospective, randomized study, 50 patients with clinical signs of medial meniscal injury were allocated to two groups, A and B. The patients in group A received 40 mL of 0.25% bupivacaine while the same dose of bupivacaine combined with 1 mg of morphine sulphate was administered in group B. Pain was estimated using the visual analogue scale (VAS) during surgery and at 2, 4, 6, and 24 hours after the operation was completed. Supplementary analgesic requirements were also registered, as well as the patients' overall rating of the entire procedure. The pain scores were significantly lower in Group B throughout the whole postoperative observation period. However, no significant differences were found between the two groups in terms of intraoperative pain scores, supplementary analgesic requirements, or the overall rating of the procedure. This study provides evidence that arthroscopic surgery can be performed in a safe manner after intra-articularly administered bupivacaine with or without low-dose morphine. The combination of low-dose morphine and bupivacaine did, however, produce a superior postoperative analgesic effect during the 24 hours following knee arthroscopy compared with bupivacaine alone.     

硒和维生素E对克山病病区粮喂饲大鼠心肌纤维化的影响

目的:观察适时适量补充硒(Se)和维生素E(VE)对心肌纤维化和心肌重构的影响,探讨克山病病区的低Se和低VE膳食是否在心肌损伤后的修复过程中持续发挥作用.方法:30只Wistar 大鼠随机分为:正常对照组(Control,混合饲料喂养)、病区粮饲料组(EG,病区粮喂养)、病区粮饲料加Se组(EG+Se)、病区粮饲料加VE组(EG+VE)和病区粮饲料加Se加VE组(EG+Se+VE).喂养21 d后,取大鼠心脏,比色法测定大鼠血清中谷胱甘肽过氧化物酶(GSH-Px)活力;硫代巴比妥法测定血清丙二醛(MDA)含量;马松三色染色测定大鼠细胞外基质沉积情况;免疫组织化学法和Western blotting法测大鼠心肌组织中转化生长因子β(TGF- β)和结缔组织生长因子(CTGF)表达.结果:与正常对照组比较,EG组心肌纤维化大鼠血清中GSH-Px活力下降(P<0.01),MDA含量升高(P<0.05),心肌组织胶原蛋白大量沉积,并伴有TGF-β和CTGF表达上调(P<0.01).与EG组比较,EG+Se组和EG+Se+VE组病区粮心肌纤维化大鼠血清中GSH-Px活力均提高(P<0.01 和P<0.05),MDA含量降低(P<0.05);大鼠心肌细胞外基质沉积缓解;克山病大鼠心肌TGF- β和CTGF表达下调(P<0.01).结论:低Se和低VE在心肌损伤后的修复过程中持续发挥作用,适时适量补充Se和VE有利于减轻和逆转过度的心肌纤维化和心肌重构.     

冷原子吸收法测定环境水样中汞的探讨

通过比较环境水样中汞的常用测定方法，重点介绍冷原子荧光法，并通过实验探讨水样的保存，SnCl2溶液的最佳保存方式及稳定期。