农药微囊悬浮剂成囊率测定

成囊率是评价农药微囊质量的一个重要指标。以30％辛硫磷微囊悬浮剂为例,初步建立了成囊率的测定方法。结合囊皮和农药有效成分的特点,选用乙二醇水溶液作为特殊溶剂。该溶剂既不破坏囊皮,又不影响囊内有效成分,且能溶解游离的有效成分。经玻璃纤维过滤,将微囊完全分离出来,可测出囊内有效成分含量。另外,选用甲醇作溶剂,经强超声破囊后,可测出有效成分的总含量。并对该方法进行了方法学的考察,证明了样品前处理方法科学、快捷,为工业化生产质量检测提供了可靠的保证。     

Adaptation of CIELAB CMC Acceptability Formulase to the Problem of Metamerism ( a 3-Light Special Index of Metamerism)

I have used the metamerism equation for the past two years on hundreds of colors. I have found the equation's agreement with visual evaluation to be a useful tool in color-matching situations. I would appreciate any feedback on the use of this equation. I can be reached at (614) 297-6138 or fax your comments to (614) 297-2912.     

季铵盐体系金的萃取与反萃

在碱性条件下研究了十六烷基三甲基溴化铵(CTAB)微乳液体系萃取KAu(CN)2. 实验考察了水相金浓度、反萃液中卤素离子、NH4SCN及羟乙基硫醚浓度对金萃取和反萃的影响及有机相中水含量与金萃取的关系. 结果表明：CTAB/己醇/庚烷微乳液体系可将绝大部分金从水相萃取到有机相;随着萃入金的增加,有机相水含量减少. 卤素离子的反萃能力顺序为：KI>KBr>KCl;高KI浓度(>2.0 mol/L)可将有机相中绝大部分(94%)的金反萃出来. 羟乙基硫醚及NH4SCN也是金的良好反萃剂,两者混合可以降低反萃液粘度,又可以减小NH4SCN浓度,而保持较高的金反萃率.     

The toxicity of pesticides for livestock

Conclusion In this discussion I have covered the relationship of toxicity to hazard, and I have argued that normally expected residues of pesticides on forage are practically never a hazard to livestock, but that some of the pesticides are stored in the tissues of livestock and excreted in their milk, creating a potential hazard to people. This hazard can be avoided by carefully following label instructions as to dosage and proper intervals which must occur between treatment and harvest of slaughter. I have indicated that chemical analyses are of virtually no value for diagnostic purposes. I have pointed out that all the toxicological information developed for a given compound can be utilized only if the manufacturer, formulator, and consumer contribute equally to safe, intelligent usage. The manufacturers and formulators must prepare the compounds in stable, readily usable form, and devise labels for the final product, which will clearly define the intended uses and limitations of the product. The consumer must read the label and adhere strictly to the suggestions found there. I believe that the rational use of pesticides in agriculture is essential if we are to maintain maximum productivity in the face of constantly shrinking farm and ranch land and an exploding population. I believe that these materials can be, and are being, used with complete safety to man and animals when label instructions are followed.     

Modeling Study on a Three-Zone Simulated Moving Bed without Zone I

A three-zone SMB was proposed to reduce the adsorbent usage, where zone I normally used to regenerate the adsorbent is discarded and the desorbent is directly pumped into zone II. An analysis on the movement of the concentration band indicates that the tail of the more retained solute is desorbed successively in zones II and IV, without overlapping with the front of the less retained solute in zone IV. As a result, the raffinate and extract product can be collected from the outlets of zones III and IV, respectively. The model simulations confirm that the three-zone SMB dropping zone I can lower the adsorbent usage and system pressure without losing the purity. In comparison with the four-zone SMB and another three-zone SMB dropping zone IV, the solvent consumption is lower than that by the latter, but higher than that by the former. The partial withdrawal operation can reduce the solvent consumption in the two SMBs without zone I and without zone IV. For anti-Langmuir isotherm dropping zone I is more effective than dropping zone IV.     

Protective Effects of Mitochondrial Uncoupling Protein 2 against Aristolochic Acid I-Induced Toxicity in HK-2 Cells

Aristolochic acid I (AA I) is one of the most abundant and toxic aristolochic acids that is reported to cause Aristolochic acid nephropathy (AAN). This paper was designed to assess whether mitochondrial Uncoupling Protein 2 (UCP2), which plays an antioxidative and antiapoptotic role, could protect human renal proximal tubular epithelial (HK-2) cells from toxicity induced by AA I. In this study, HK-2 cells were treated with different concentrations of AA I with or without UCP2 inhibitor (genipin). To upregulate the expression of UCP2 in HK-2 cells, UCP2-DNA transfection was performed. The cell viability was evaluated by colorimetric method using MTT. A series of related biological events such as Reactive Oxygen Species (ROS), Glutathione peroxidase (GSH-Px), and Malondialdehyde (MDA) were evaluated. The results showed that the cytotoxicity of AA I with genipin group was much higher than that of AA I alone. Genipin dramatically boosted oxidative stress and exacerbated AA I-induced apoptosis. Furthermore, the increased expression of UCP2 can reduce the toxicity of AA I on HK-2 cells and upregulation of UCP2 expression can reduce AA I-induced oxidative stress and apoptosis. In conclusion, UCP2 might be a potential target for alleviating AA I-induced nephrotoxicity.     

Roles of Nitric Oxide in Brain Ischemia and Reperfusion

Brain ischemia and reperfusion (I/R) is one of the most severe clinical manifestations of ischemic stroke, placing a significant burden on both individuals and society. The only FDA-approved clinical treatment for ischemic stroke is tissue plasminogen activator (t-PA), which rapidly restores cerebral blood flow but can have severe side effects. The complex pathological process of brain I/R has been well-established in the past few years, including energy metabolism disorders, cellular acidosis, doubling of the synthesis or release of excitotoxic amino acids, intracellular calcium homeostasis, free radical production, and activation of apoptotic genes. Recently, accumulating evidence has shown that NO may be strongly related to brain I/R and involved in complex pathological processes. This review focuses on the role of endogenous NO in pathological processes in brain I/R, including neuronal cell death and blood brain barrier disruption, to explore how NO impacts specific signaling cascades and contributes to brain I/R injury. Moreover, NO can rapidly react with superoxide to produce peroxynitrite, which may also mediate brain I/R injury, which is discussed here. Finally, we reveal several therapeutic approaches strongly associated with NO and discuss their potential as a clinical treatment for ischemic stroke.     

Formation of L Amino Acids and D Sugars,and Amplification of their Enantioexcesses in Aqueous Solutions,Under Simulated Prebiotic Conditions

The Murchison meteorite delivered five α-methyl amino acids to Earth with small excesses of the L enantiomer; later, additional examples were found and such compounds were also found in other meteorites. I describe our work using them under prebiotic conditions to form normal proteinogenic amino acids with an excess of the L enantiomers, and to amplify such excesses to dominant concentration in solution. I also extend this work to show how D sugars, such as D -ribose, can have been formed and amplified in solution. I also show the high concentration amplifications of D -nucleosides that can be obtained under credible prebiotic conditions. The simple theory of such amplifications, and corrections resulting from solvation effects, are described along with modern ideas of the source of such α-methyl amino acids in meteorites.     

Ultrafast synthesis of Au(I)-dodecanethiolate nanotubes for advanced Hg2+ sensor electrodes

In this work, an ultrafast and facile method is developed to synthesize Au(I)-dodecanethiolate nanotubes (Au(I)NTs) with the assistance of glycyl-glycyl-glycine (G-G-G). Transmission electron microscopy (TEM) images reveal that the as-prepared Au(I)NTs can be obtained in a 2-h reaction instead of a previous 24-h reaction and are uniform with a hollow structure and smooth surface by virtue of the G-G-G peptide tubular template. According to structural analysis, a possible preparative mechanism is proposed that the G-G-G peptide could help to curl into tube-like morphology in alkaline situation spontaneously to accelerate the formation of Au(I)NTs. Meanwhile, PVDF-stabilized Au(I)NT-modified glassy carbon electrodes present their promising potential for Hg²⁺ detection.     

近期纯碱生产的发展与一种同时生产氯乙烯和纯碱的非电解过程

荷兰阿克苏化学公司采用一种非电解的同时生产纯碱和氯乙烯的ＡＺＣ过程，希望降低能耗费用的二分之一。过程采取多循环系统的技术形式。实质是一个催化有机循环。循环流体组成为约３５％的己二腈，其余为Ｉ２Ｃｌ－等复合离子。流体在压力下吸收乙烯，乙烯与Ｉ２Ｃｌ－反应生成碘氯乙烷和Ｉ－。碘氯乙烷转化为二氯乙烷。二氯乙烷被转化为氯乙烯。下一步骤是此流体在加入纯固体食盐而析出ＮａＨＣＯ３，ＮａＨＣＯ３被煅烧成纯碱。     

生长抑素基因在大肠杆菌pThioHis表达系统中的克隆与表达

目的　在大肠杆菌表达系统中高效表达生长抑素 (SS)基因。方法　以天然SS的氨基酸和基因序列为标准 ,将大肠杆菌使用频率较低的密码子分别更换成了使用频率较高的密码子 ,在SS基因的两端加上了合适的酶切位点 ,头部 :KpnI和NcoI;尾部 :PstI(这一酶切位点可与NsiI的切口互补 )。克隆至pThioHisA质粒的KpnI/PstI酶切位点后 ,再克隆至pThioHisA质粒的KpnI/NsiI酶切位点 ,使SS基因分别位于多克隆位点的尾部和前部。结果　重组质粒经酶切鉴定和基因序列测定证明 ,基因完全正确 ,在大肠杆菌TOP10中均得到较好的表达 ,IPTG诱导后 4h表达量基本达到最高 (37℃ ) ;在A60 0 0 .4～ 1.5之间用IPTG诱导均可获得到较好的表达 ,但以 0 .6左右为最佳诱导时机 ;在LB、TB和 2YT培养基中表达量依次为 :TB >LB >2YT ;表达的SS融合蛋白基本为水溶性的 ,具有良好的SS抗原性和免疫原性。结论　为基因工程SS大肠杆菌疫苗的研制奠定了基础     

胶粘剂及其用量对活性炭胶炭混合物液相吸附性能的影响

胶粘剂与粉状活性炭按不同的胶炭比混合、干燥、研磨得粉状胶炭混合物。测定了碘吸附值、亚甲基蓝脱色力和焦糖脱色力3种液相吸附力,讨论了原料活性炭、胶粘剂的种类和用量对活性炭成型物液相吸附能力的影响。结果表明胶接过程中,原料活性炭液相吸附力的劣化按碘吸附值、亚甲基蓝脱色力、焦糖脱色力的顺序而变得越来越严重,并随所使用胶粘剂分子质量的减小和用量的增加而加剧;原料活性炭的碘吸附值的损失率一般不超过10%,而焦糖脱色力的损失率几乎都达到了100%。用本方法制备的活性炭成型物的液相吸附特征是:适于吸附碘之类的小分子,具有在一定范围内可调整的较低的亚甲基蓝脱色力,而对焦糖色素之类的液相大分子的吸附力几乎为零。     

Antioxidants and stabilizers, 98. An investigation of the synergism between N-isopropyl-N′-phenyl-1,4-phenylenediamine and 2,6-dialkylphenols

The rubber antidegradant, N-isopropyl-N′-phenyl-1,4-phenylenediamine ( I ), after being oxidized to N-isopropyl-N′-phenyl-1,4-benzoquinonediimine ( II ) may again be partly regenerated by a reaction with 2,6-dimethylphenol with the simultaneous formation of a compound containing one fragment derived from 2,6-dimethylphenol and two fragments derived from I . For this compound we suggest structure IV (a, b, or c). This compound readily decomposes, yielding a further molecule of antidegradant I . The cooperative effect between I and 2,6-dimethylphenol can also be seen in the autoxidation of squalene. The behaviours of some further simple alkyl derivatives of phenol in a reaction with II are described.     

Bubble column fermenter modeling: A comparison,for pressure effects

Two models which describe the oxygen transfer, oxygen uptake, and axial mixing in a bubble column fermenter are described. Model I includes no pressure effects and can be solved analytically. Model II incorporates the influence of hydrostatic pressure on oxygen solubility and gas expansion and must be solved numerically. The liquid phase oxygen concentration profiles as obtained from both models are compared to ascertain for what parametric conditions and for what maximum column height Model I is valid. The results show that for many situations Model I can approximate the oxygen profiles in a 10 m column within 20%. As the transfer and uptake rates increase the deviation of Model I can reach 80% for a 10 m column.     

Polymorph prediction of organic pigments

The crystal structure of several industrially important organic pigments namely C.I. Pigment Violet 23, C.I. Pigment Red 202 and C.I. Pigment Yellow 139 were predicted using the Cerius² Polymorph Predictor in combination with XRPD patterns. After generation and energy minimisation of the candidate structures for each pigment, their calculated powder patterns were compared with those obtained experimentally using X-ray diffraction. The structures which best fitted the experimental powder patterns were regarded as possible structures of the compound; finally, a rigid body Rietveld refinement was performed to validate the choice of the structure. The structure of C.I. Pigment Violet 23 has not previously been published while the predicted structures of C.I. Pigment Red 202 and C.I. Pigment Yellow 139 were in accordance with the published structures. The work demonstrates that pigment crystal structure can be predicted using a low quality X-ray powder diffraction pattern.     

固体酸S_2O_8~(2-)/Fe_2O_3-SiO_2催化制备马来酸二己酯

在铁氧化物中引入硅的氧化物 ,并用S2 O82 -浸渍铁硅复合氧化物 ,制得固体酸催化剂S2 O82 -/Fe2 O3 SiO2 (Ⅰ )。用马来酸酐与正己醇的酯化反应考察了催化剂的活性。通过XRD和TEM分析 ,对催化剂的结构进行了表征。结果表明 ,Ⅰ的最佳制备条件为 :n(Fe)∶n(Si)为 5∶1、70℃陈化 3h ,2 0 0℃焙烧 2h、用 0 2 5mol/L的 (NH4) 2 S2 O8浸渍 3h、在 5 5 0℃下煅烧 6h ;Ⅰ的催化活性比S2 O2 -8/Fe2 O3 和SO2 -4/Fe2 O3 SiO2 更强 ,S2 O2 -8对Fe2 O3 SiO2 的促进作用明显高于SO2 -4;SiO2 的引入提高了催化剂的分散效果 ;有较好的使用重复性 ;它代替硫酸、对甲苯磺酸用于催化马来酸酐和正己醇的酯化反应可得无色透明的酯化产物     

用198Au示踪法研究季铵盐体系萃取金

The solvent extraction of KAu(CN)2 from alkaline solution by quaternary ammonium salts (trialkylmethylammonium chloride or cetyltrimethylammonium bromide) waw investigated by means of ^198Au radioactive tracer method. Various parameters,such as the gold (I) concentration in aqueous phase,the modiffer,emulsifiation at the interface of two phases, and phase ratio used in the extraction of gold (I) were studied. The results demonstrate that almost all gold (I) in the aqueous phase was practically extracted into the organic phase. The water content in the organic phase decreased significantly with increase of gold (I) concentration using long chain alcohol as modifier,in contrast with the system with tributyl phosphate (TBP) as modifier. Emulsification at the interface of two phases decreases with an increase of modifier concentration in the organic phase or with the addition of a small amount of lysozyme into the aqueous phase. The method with ^198Au tracer can be directly used to determine the Au(I) concentration both in aqueous and organic phases, which is especially suitable for the low concentration of Au(I).     

Pigment Yellow G583-a misclassified pigment and its relationship with other acetoacetanilide azo pigments

Pigment Yellow G583 (nominally C.I. Pigment Yellow 6) has been compared with another version of C.I. Pigment Yellow 6 (Recolite Fast Yellow 3G) and the colour and the X-ray powder diffraction pattern have been found to be different. Density measurements, crystal structure analysis and chemical analysis have shown that the former is a mixed crystal of60 mol% C.I. Pigment Yellow 6 and 40 mol% C.I. Pigment Yellow 5. Pigment Yellow G583 was then compared crystallographically with a series of similar pigments, and it has been concluded that the structure of C.I. Pigment Yellow 6 is different to that of all the others. Regardless of composition, Pigment Yellow G583 is a mixed crystal of C.I. Pigment Yellow6 molecules in an α-C.I. Pigment Yellow 5 lattice and not vice versa. This does not necessarily make Pigment Yellow G583 a poor pigment, but a change of composition may cause the crystal lattice to become that of C.I. Pigment Yellow 6, changing the physical properties. The only way in which a change of crystal structure can be detected is to examine the X-ray diffraction pattern.     

Biopolymer based ion imprinting cryogel traps for the removal of Tl(I)

The aim of this study is to prepare supermacroporous cryogel with embedded ion imprinted polymer (IIP) particles which can be used for the selective removal of Tl(I) from aqueous solution. In the first step, Tl(I) has complexed with chitosan and crosslinked with ephychlorohydrin. In the second step, the supermacroporous poly(hydroxyethyl methacrylate) (PHEMA) cryogel with embedded IIP particles [PHEMA/MIP composite cryogel] which have been produced by free radical polymerization initiated by N,N,N’,N’-tetramethylene diamine (TEMED) and ammonium persulfate (APS) pair in ice bath. The template, Tl(I), has been removed from the polymer using 0.1 M EDTA solution. The cryogel is characterized by swelling test, scanning electron microscopy, and Fourier transform infrared spectroscopy. The effective parameters on Tl(I) adsorption process have evaluated by investigating the dependency of the adsorption capacity on flow-rate, Tl(I) concentration and contact time. The maximum adsorption capacity of Tl(I) ions has been found to be 1.55 µgg^?1. The selectivity of the IIP biopolymer cryogel has investigated by competitive adsorption of Cd(II), Cu(II), K(I), and Fe(II). The relative selectivity coefficients of IIP biopolymer cryogel are 3.98 and 62.5 for Cd(II) and Cu(II), respectively. The IIP biopolymer cryogel could be used many times without any significant decrease in the adsorption capacity. As a conclusion it can be said that the IIP biopolymer cryogel could be used for specific separation of Tl(I) ions from nuclear, industrial, and environmental waste.