Interpretation of Diffusion Susceptibility Data Obtained with 50-μg Carbenicillin Discs Against Gram-Negative Organisms

A total of 284 clinical isolates of various species of Enterobacteriaceae, Pseudomonas aeruginosa, P. maltophilia, and Acinetobacter anitratum were tested for susceptibility to carbenicillin by the standardized Bauer-Kirby disc diffusion technique and a microtiter broth dilution method. The data obtained led to the following proposed criteria for the interpretation of the results of disc susceptibility tests. Enterobacteriaceae that yield zones of inhibition equal to or greater than 20 mm in diameter around 50-mug discs of carbenicillin are designated as sensitive to the drug; isolates that yield zones measuring from 18 to 19 mm in diameter are reported as of equivocal (intermediate) susceptibility to the drug, whereas those enterobacterial isolates that are characterized by zones of inhibition of 17 mm or less in diameter are interpreted as resistant to carbenicillin. Isolates of P. aeruginosa, P. maltophilia, and A. anitratum yielding zones of 14 mm or more in diameter around 50-mug discs of carbenicillin are reported as sensitive, whereas those isolates that are characterized by zones of 13 mm or less in diameter are reported as resistant to this drug.     

No meaningful increase in urinary tubular dysfunction markers in a population with 3μg cadmium/g creatinine in urine

The critical Cd exposure level to induce tubular dysfunctions is a focus of public concern among general populations in Japan. To answer this question, one group each (about 1000 adult women/area) in nonpolluted areas with high (Area H) and low Cd exposure (Area L) was obtained, and 742 strictly age-matched pairs of never-smoking adult women were selected for comparison. Cd, α₁-MG (microglobulin) and β₂-MG in urine were taken as markers of exposure and tubular dysfunction, respectively. Geometric mean Cd levels as corrected for creatinine (Cd_cr) was greater than three times higher in Area H (2.8 μg/g cr) than in Area L (0.8 μg/g cr). Nevertheless, β₂-MG_cr did not differ between the two areas (125 μg/g cr for Area H vs 118 μg/g cr for Area L). α₁-MG_cr was only marginally higher in Area H (2.8 mg/g cr) than in Area L (2.1 mg/g cr), with no biomedical significance. Results were essentially the same when analyses were conducted with noncorrected observed values or values corrected for a specific gravity. Thus, the effects of Cd exposure in Area H on renal tubular function should be essentially nil.     

Using a Wetland Bioreactor to Remediate Ground Water Contaminated with Nitrate (mg/L) and Perchlorate (μg/L)

Wetland plants and their rhizospheric microorganisms were used to remove perchlorate from nitrate-contaminated ground water. A wetland bioreactor was constructed with the wetland plants Typha spp., Scirpus spp., and Cyperus spp. These plants provided a habitat and a food source for the indigenous denitrifying microorganisms presumed responsible for the perchlorate and nitrate removal. Ground water contaminated with nitrate (68 mg/L) was collected from a well and injected with concentrations of potassium perchlorate similar to those found in several local wells (50 and 100 μg/L). The water flowed continuously through the wetland bioreactor with hydraulic retention times (HRT) ranging from 0.5 to 400 h. Because microbial denitrification depends, in part, on the nature and amount of carbon available to the microorganisms, four carbon sources (dried leaf matter, dried algae, milk replacement starter, and sodium acetic acid) were evaluated. Analyses for perchlorate

This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes.

Work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract W-7405-Eng-18. concentration in ground water were performed using negative electrospray mass spectrometry/mass spectrometry. Of the carbon sources tested, sodium acetic acid was the most efficient at accelerating the nitrate and perchlorate removal rates. The HRT required to remove perchlorate (100 μg/L) to below the detection limit, without carbon source amendment, was 4 d. With the addition of sodium acetic acid (0.26 g/L) the required HRT decreased to 0.5 d. These results suggest that denitrifying microorganisms, supported in a wetland bioreactor amended with a carbon source, remove perchlorate from nitrate contaminated ground water.     

How does the 50/500 rule apply to MVPs?

The 50/500 rule has been used as a guiding principle in conservation for assessing minimum viable effective population size (N(e)). There is much confusion in the recent literature about how the 500 value should be applied to assess extinction risk and set priorities in conservation biology. Here, we argue that the confusion arises when the genetic basis for a short-term N(e) of 50 to avoid inbreeding depression is used to justify a long-term N(e) of 500 to maintain evolutionary potential. This confusion can result in misleading conclusions about how genetic arguments alone are sufficient to set minimum viable population (MVP) thresholds for assessing the extinction risk of threatened species, especially those that emphasize that MVPs should be in the thousands to maintain evolutionary potential.     

两剂10μg乙型肝炎血源疫苗对儿童和新生儿的免疫效果

1985年在河北正定县吴兴乡,用放射免疫法检测HBsAg、抗-HBs和抗-HBc。选取15岁以下HBV易感儿童630名,按0、3个月程序肌注北京生物制品研究所生产的乙型肝炎血源疫苗(HB疫苗),剂量为每剂10μg,全程接种率为77.6％(488/630)。 1.在免疫后1、2、3、4、5年检测抗-HBs,其阳转率分别为87.2％(143/164)、87.4％(132/151)、85.6％(185/216)、76.4％(81/166)和75.5％(200/285);其S/N值的GMT分别为71.6、61.2、57.7、41.5和35.5。     

50g/L虱螨脲乳油对草地贪夜蛾的室内活性和田间药效研究

试验50 g/L虱螨脲乳油对草地贪夜蛾的室内活性及田间药效。以饲喂法测试虱螨脲对草地贪夜蛾3龄幼虫的室内活性,以喷雾法测定50 g/L虱螨脲乳油在玉米不同生长发育期的田间药效。室内测定结果表明,20 mg/L虱螨脲对草地贪夜蛾3龄幼虫有较好的毒杀作用,经其处理3 d后的死亡率为80%,处理4 d后的死亡率为98.33%。田间试验结果表明,50 g/L虱螨脲乳油在玉米拔节期施药效果最好,穗期防效一般,花粒期防效较差,750倍药液处理7 d后的防效分别为93.07%、64.24%和43.21%。50 g/L虱螨脲乳油可用于防治玉米草地贪夜蛾,推荐施药时间为玉米喇叭口期前,施药浓度为750倍液。     

新生儿接种10μg3针乙型肝炎血源疫苗5年内的免疫效果观察

1986～1958年,对广东3个城市1～5岁儿童乙型肝炎病毒(HBV)感染做横断面调查的基础上,给新生儿普种乙型肝炎血源疫苗。出生后24小时内接种1针,1、6个月接种第、3针,每针10μg,共接种1万余名。免疫后抽查HBsAg阳性母亲新生儿血380人份,HBsAg阴性母亲新生儿血1466人份。同时采集同期出生的未免疫的新生儿血116份作为内对照。以放射免疫法(RIA)检测HBV指在。结果,新生儿免疫后1～5年,标化抗-HBs阳转率为67.3％～79.1％。免疫后1～5年HBsAg阳性率与免前HBsAg阳性率比较,其保护率为65.8％～92.1％;与平行内对照的HBsAg阳性率比较,保护率为58.6％～88.1％。且发现HBsAg阳性母亲的新生儿,随免疫年限延长,HBsAg阳性率有降低趋向。     

1g/h与2g/h硫酸镁维持剂量输注期间的血清镁水平预防子痫效果

摘要 目的：探究硫酸镁不同维持剂量在预防子痫中的临床效果分析。方法：选择2018年1月至2020年1月于我院接受治疗的100例子痫前期产妇,按照随机数字表法区分为研究组与对照组（每组各50例产妇）,对照组产妇接受1 g/h硫酸镁维持剂量输注,研究组产妇接受2 g/h硫酸镁维持剂量输注,对比两组产妇干预前后血压、24 h尿蛋白、血浆纤维蛋白原、尿钙黏蛋白变化,统计两组产妇临床疗效差异以及不良反应发生情况。结果：（1）研究组治疗总有效率为98.00 %,高于对照组的86.00 %（P<0.05）;（2）干预前两组产妇收缩压和舒张压组间无差异（P>0.05）,治疗后研究组收缩压和舒张压均低于对照组（P<0.05）;（3）干预前两组产妇24 h尿蛋白、血浆纤维蛋白原水平组间无差异（P>0.05）,治疗后研究组上述指标均低于对照组（P<0.05）,但两组干预前后血清镁水平无差异（P>0.05）;（4）研究组不良反应总发生率14.00 %,显著高于对照组的2.00 %（P<0.05）。结论：对子痫产妇持续输注2 g/h硫酸镁可以有效改善其临床症状,降低产妇血压水平,控制其疾病进展效果较好,但不良反应发生情况显著高于持续输注1 g/h硫酸镁的产妇。     

Nematode resistance to ivermectin (630 and 700 μg/kg) in cattle from the Southeast and South of Brazil

Two high doses of ivermectin (630 μg/kg and 700 μg/kg) that are sold commercially in Brazil were evaluated in dose-and-slaughter trials with 144 naturally nematode-infected cattle from eight regions within the states of Minas Gerias, São Paulo and Rio Grande do Sul in Brazil. Treatment groups were based on fecal egg counts 1, 2, and 3 days before treatment; all animals studied had a minimum egg count of at least 500 eggs per gram of feces (EPG). Post-mortem analyses were conducted on day 14. The highest levels of resistance to ivermectin were found for Haemonchus placei, Cooperia punctata and Oesophagostomum radiatum; all populations of H. placei were resistant to the 630 μg/kg dose, and 67% were resistant to 700 μg/kg; 86% of C. punctata were resistant to the 630 μg/kg dose, and 33% were resistant to 700 μg/kg. A combined analysis revealed that 57% of O. radiatum were resistant to the lower dose of ivermectin. H. placei, C. punctata and O. radiatum, in order, were the nematode populations with the highest indices of resistance, whereas Trichostrongylus axei was the most susceptible to 630 and 700 μg/kg dosages of ivermectin. The results of helminthic resistance to ivermectin for different populations of H. placei and C. punctata described in the present study support previous literature data, in which a small decrease in the average parasitic burden of C. punctata and a consequent increase of H. placei were observed in cattle from the Southeast, South and Center-West regions of Brazil.     

Microsecond Single-Molecule Tracking (μsSMT)

Here we report on a method to track individual molecules on nanometer length and microsecond timescales using an optical microscope. Our method is based on double-labeling of a molecule with two spectrally distinct fluorophores and illuminating it with laser pulses of different wavelengths that partially overlap temporally. We demonstrate our method by using it to resolve the motion of short DNA oligomers in solution down to a timescale of 100 μs.     

Chalcogenide-capped triruthenium clusters: X-ray structures of [Ru3(CO)6(μ3-CO){P(C4H3S)3}(μ-dppm)(μ3-O)] and [(μ-H)2Ru3(CO)6{P(C4H3S)3}(μ-dppm)(μ3-S)]

Treatment of [Ru₃(CO)₉{P(C₄H₃S)₃}(μ-dppm)] (1) [dppm = bis(diphenylphosphino)methane] with molecular oxygen in benzene at 60 °C affords oxo-capped [Ru₃(CO)₆(μ₃-CO){P(C₄H₃S)₃}(μ-dppm)(μ₃-O)] (2), while with elemental sulfur and selenium related chalcogenide-capped clusters [Ru₃(CO)₆(μ₃-CO){P(C₄H₃S)₃}(μ-dppm)(μ₃-E)] (3, E = S; 5, E = Se) and bis(chalcogenide) clusters [Ru₃(CO)₆{P(C₄H₃S)₃}(μ-dppm)(μ₃-E)₂] (4, E = S; 6, E = Se) result. Reaction of 1 with H₂S in refluxing THF affords the previously reported [(μ-H)₂Ru₃(CO)₇(μ-dppm)(μ₃-S)] (7) together with the new sulfido-capped dihydride [(μ-H)₂Ru₃(CO)₆{P(C₄H₃S)₃}(μ-dppm)(μ₃-S)] (8). All new compounds have been characterized by spectroscopic data, and 2 and 8 by single-crystal X-ray diffraction analyses. Oxo-capped 2 consists of a triangular ruthenium framework capped on opposite sides by oxo and carbonyl groups, while 8 consists of a ruthenium triangle by a capping sulfido ligand and two inequivalent bridging hydride ligands.     

Hyponitrite complexes: Crystal and molecular structure of [Ru2(CO)4(μ-PBu2)(μ-Ph2PCH2PPh2)(μ-η-ONNOMe)]

The new trans-hyponitrite derivative complex [Ru₂(CO)₄(μ-P^tBu₂)(μ-dppm)(μ-η²-ONNOMe)] (2, dppm = Ph₂PCH₂PPh₂) was prepared by deprotonation of [Ru₂(CO)₄(μ-H)(μ-P^tBu₂)(μ-dppm)(μ-η²-ONNOMe)][BF₄] (1) with the base DBU (1.8-diazabicyclo[5.4.0]undec-7-ene). The latter complex salt has been obtained in an improved synthesis starting from the trans-hyponitrite complex [Ru₂(CO)₄(μ-H)(μ-P^tBu₂)(μ-dppm)(μ-η²-ONNO)]. Compound 2 has been characterized by spectroscopic methods as well as by X-ray diffraction and represents the first neutral complex bearing a deprotonated monoester of the hyponitrous acid as the bridging ligand.     

50亿只漂泊鸠去向何方?

近一百年前,在北美的天空时常飞翔着一种鸟群。在它所到之处,刹时间天昏地暗,犹如发生了日蚀一般。整个天幕几乎全都遮住了,鸟粪雪片似地从天而降,扑翼声犹如狂风呼啸。好几个小时过去了,鸟儿仍在飞着,飞着,它们的行军队伍无边无际。无论是喊叫,无论是枪击或者炮轰,都不能使这蝗群似的数不胜数的“航空大队”偏离航向。这种鸟,就是属于鸽形目的漂泊鸠(Ectopistes migratorius)。     

生物检材中佐匹克隆的GC/μECD测定

目的：建立液-液萃取、GC/μECD气相色谱测定生物检材中佐匹克隆的方法。方法：以家兔为模型动物,500 mg佐匹克隆标准品灌胃家兔,6.5小时后处死,取其胃、肝、血、脑、心脏、尿,采用乙醚液-液萃取提取,Rtx-5毛细管柱分离,电子捕获检测器检测,标准曲线法定量。结果：该方法灵敏度达0.02μg/mL,在0.05-50μg/mL范围内线性关系良好;低、中、高3种浓度的加样回收率分别为91.7%、99.5%、94.4%,相对标准偏差（RSD）均小于5%;佐匹克隆在家兔脏器中的浓度分别为7.31μg/mL（血液）、7.63μg/g（肝脏）、7.96μg/g（脑）、14.67μg/g（心脏）、32.18μg/g（胃组织）、42.65μg/mL（尿液）,在各脏器中呈特异性分布。结论：该法操作简单、灵敏度高,结果可靠,完全满足临床检测及公安机关在办理佐匹克隆麻醉案件中的需要。     

Logistic方程中的速度参数(μ_L)等于种群的内禀增殖率(μ_m)吗?

众所周知,在养分等环境条件不受限制时,种群增殖遵循Malthus方程,形为: dx/xdt=μ_m (1) 此处,x为种群密度;t为时间;μ_m称为内禀增殖率,意为种群不受养分等环境因素限制时的一种取决于种群内部特性的最大可能增殖比速度(或增殖率)。在养分等环境条件有限时,常引用Logistic方程,形为:     

Transformation of androgenic-derived Festulolium plants (Lolium?perenne L.?×?Festuca?pratensis Huds.) by Agrobacterium?tumefaciens

Genetic transformation of androgenic-derived amphidiploid Festulolium plants (Lolium perenne L. × Festuca pratensis Huds., 2n = 4x = 28) by Agrobacterium tumefaciens has been achieved. Anther culture-induced calli of Festulolium “Bx351” were inoculated with Agrobacterium tumefaciens strain LBA4404 carrying pIG121-Hm encoding the hygromycin resistance (hph) and β-glucuronidase (uidA) genes under the control of a CaMV 35S promoter. Twenty-three putative transformants were obtained from the hygromycin selection, 19 of which (82.6%) showed GUS activity. The integration of transgene was detected by using genomic DNA PCR analysis, RT-PCR analysis and Southern blot hybridization, respectively, which revealed that foreign gene was integrated into the genomes of dihaploid transformants (2n = 2x = 14). The haploid embryogenic system offers a stable means of transformation, as the introduced trait can be readily fixed through chromosome doubling. An erratum to this article can be found at