Effect of ultraviolet irradiation on eggs and larvae on the northern anchovy, Engraulis mordax, and the Pacific mackerel, Scomber japonicus, during the embryonic stage.

Abstract— Anchovy and mackerel eggs and yolk-sac larvae were exposed to UV radiation in the bioactive band of wavelengths between 280 and 320 nm. the UV-B region of the spectrum. Irradiation levels were based upon predicted UV-B increases that would result from anthropogenic diminution of Earth's protective ozone shell. Dose-response relationships for mortality and histological and morphological effects were determined for two different spectral energy compositions, using FS-40 sunlamps and two filter combinations. Anchovy were more sensitive than mackerel to UV-B. Data for anchovy were analyzed in terms of DNA-effective doses, i.e. the integrated spectral thence (in J/m²/nm) with the energy at each nm weighted by its effectiveness relative to the Setlow generalized DNA action spectrum. Fifty per cent of anchovy survived a cumulative DNA effective dose of 1150J'm^-2 over a 4-day period. In the surviving larvae. irradiation induced lesions in the brain and eye. caused marked dispersion of pigment within melanophores and retarded growth and development. At the lowest dosage used. 760 (J. m^-2)_DNA, growth was retarded and brain lesions occurred in anchovy. Calculations of Smith and Baker (in this issue) indicate that in clear ocean water a significant incidence of lesions and retardation of growth in anchovy could occur at the surface at a 25%, reduction in ozone and down to 3.5 m at a 50% reduction. Eggs and larvae of anchovy occur at these depths.     

Observations of the effect of anionic, cationic, neutral, and zwitterionic surfactants on the Belousov-Zhabotinsky reaction

In this paper we report the experimental observations of the effects of various surfactants on the oscillations of the ferroin-catalyzed Belousov-Zhabotinsky (BZ) reaction. The oscillations are followed by observing the change in absorbance at 510 nm due to ferroin in a well-stirred closed BZ reacting system. We have used sodium dodecyl sulfate (SDS) as the anionic surfactant, cetyl trimethylammonium bromide (CTAB) as the cationic surfactant, Triton X-100 as the neutral surfactant, and 3-[(3-cholamidopropyl)dimethylammonio)]-1-propanesulfonate (CHAPS) as the zwitterionic surfactant. In general, we observed that there is a change in the oscillation behavior in the presence of each of these surfactants above their critical micellar concentrations. For different surfactants, the time-dependent evolution of the oscillations is found to be characteristic of the surfactant. The results of our study suggest that the evolution of oscillations is most regular in the presence of micelles of SDS.     

Recent Progress on the Design,Characterization, and Application of Superalkalis

Superalkalis are clusters or molecules featuring lower ionization energies (IEs) than that of cesium atoms, and thus exhibit excellent reducing properties. Such special species have great potential to be used in the synthesis of unusual charge-transfer salts and cluster-assembled nanomaterials with tailored properties, in the reduction of carbon dioxide, or as hydrogen storage materials and noble-gas-trapping agents, etc. In this regard, ongoing efforts have been devoted to designing and characterizing superalkalis of new types. The recent progress on the study of superalkalis in terms of theoretical design, characterization, and potential application is summarized in this minireview. We hope this review will not only provide a broad overview of this research field, but also highlight the prospect of further extending the experimental synthesis and practical application of superalkalis.     

Recent advances on the synthesis of flavans,isoflavans, and neoflavans

Heterocyclic compounds are the omnipresent structural cores comprising many natural and pharmaceutical products of biological significance. Significantly, heterocyclic compounds are widely distributed in nature, and also have applications in agrochemicals, sanitizers, as dyestuff, as copolymers, etc. Among heterocyles, flavonoids are a class of compounds that are highly interesting and constitute many natural products. In general, all flavanoids contains a basic core of C₆-C₃-C₆ of phenyl-benzopyran backbone. The relative placement of the phenyl group on to the benzopyran core makes further classification into flavanoids, isoflavanoids and neoflavanoids. Flavans (2-aryl chroman) are subclass of anthoxanthanes exhibits a broad spectrum of biological properties such as anti-inflammatory, anti-oxidant, and anti-malarial properties. Some representative naturally occurring products possessing flavan core are apigenin, luteolin, tangeretin, scutellarein, etc. On the other hand, some of the notable isoflavan-based natural products are glabridin and (S)-(−)-equol. Glabridin is isolated from Licorice roots, which regulates paraoxonase (PON₂) levels. While the simple isoflavan (S)-(−)-equol, is produced from soy isoflavone intake. Also, natural products such as dalbergichromene, centchroman, and (+)-myristinin A possess neoflavan (4-aryl-3,4-dihydro-2H-chromenes) core structure. Owing to their broad biological and pharmacological properties, synthetic chemists are fascinated in developing new routes toward their synthesis. As a result, a decent number of reports have been established in the literature. Thus, for the past 5 years of time frame, many new methodologies have been witnessed, for the synthesis of various flavan systems. This review emphasizes most of the significant methods on accomplishing flavans, isoflavans and neoflavans and also focused on their applications to the synthesis of relevant natural as well as biologically active products.     

Comments on the electronic properties of cyclopropane,cyclobutane, and cyclohexane

Spectral quantities of cyclopropane, cyclobutane, cyclohexane, and of several derivatives, have been calculated by a semiempirical all-valence electron SCF-CI MO method. In cyclopropane, HOMO is practically localized in the carbon-frame, and LVMO is purely so. In cyclobutane, these two MO's are based on C-H bonds, while cyclohexane holds an intermediate position. Despite the overall similarity-experimental and computed-of the spectra of these molecules, assignments are non-parallel. Like cyclopropane, cyclobutane can extend conjugation, but to a diminished degree; cyclohexane behaves in this respect like an acyclic alkane. An interpretation of this gradation, in terms of the nature of high-lying MO's, is proposed.     

Dissociative adsorption of oxygen and hydrogen, and the formation of hydroxyl groups on the surface of Cu, Ag, Ni, Pd and Pt

By the semi-empirical interacting bonds method, the heats of oxygen and hydrogen adsorption in a dissociative form on the (100) face of Cu, Ag, Ni, Pd and Pt have been calculated. It has been shown that most stable are the multiply bonded adsorption forms. For the different bonding states, the heat of hydroxyl group formation from O₂ and H₂ varies but slightly. The calculated values are compared with the experimental data.

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(100) Cu, Ag, Ni, Pd, Pt. , . - H₂ O₂. .

     

An Investigation on the Effect of Arsenic Poisoning on Humans,Agriculture, and Fisheries

The purpose of this investigation is to try and understand the degree of arsenic poisoning in the waste water from agricultural chemical factories which release effluents into the waterways in their vicinity. The method of determination is to use the water samples, soil, fish, clams, shell-fish, etc. found in the areas along the canals and aqueducts and those which lie upstream, midstream, and downstream and also the hair samples of people living in the contiguous areas, to check for the levels of arsenic in them by emission spectroscopy. From the analysis during a one year investigation, we find that the level of As in the water creatures of Chungkang Stream and Lu-Er-Men Stream is much higher than in the other water areas of Taiwan such as along beaches and the other rivers; the levels in the hair of the people who live nearby these water courses have a certain degree of correspondence with their eating habits and the quantity of food eaten; however, even those people who eat relatively little have almost 3% As, beyond the 2 mg/kg limit allowed for human beings. We are fully aware of the high level of food contamination on Taiwan, and this fact has been taken into consideration. The effect of As contamination in the soil on agricultural produce does not seem to have any apparent relationship. By the way, the influence of the monthly average rainfall on As contamination in the soil is not obvious.     

Tertiary Acetylenic Alcohols,Ethers, and Esters on the Basis of Isocamphanone,Camphor, Fenchone,Isofenchone, and Adamanthanone

Acetylenic lithium alcoholates were synthesized by reactions of 1-hexyne, 1-octyne, and phenylacetylene with butyllithium with subsequent reaction of the resulting acetylides with isocamphanone, (±)-camphor, (+)-fenchone, isofenchone, and adamanthanone. The latter reaction is controlled by steric factors. Lithium alcoholates were used to synthesize the corresponding alcohols, ethers, and esters. Configurational assessment of the products was performed on the basis of quantum-chemical calculations and X-ray diffraction analysis.     

Sorption and Preconcentration of the Herbicides Atrazine,Simazine, and Ametryne on Montmorillonite

This paper describes the treatment of montmorillonite (MT), with K⁺ (MT_K), Na⁺ (MT_Na), and Ca²⁺ (MT_Ca) to explore the use of these minerals for the extraction and preconcentration of the herbicides atrazine, simazine, and ametryne from aqueous medium. In the sorption process, the three materials exhibited good performance; ametryne was totally sorbed. For atrazine and simazine, MT_K showed a removal between 90% (atrazine) and higher than 99% (simazine). The recoveries employing solutions at initial concentrations of 100 µg L^?1 of each herbicide showed results of 90% (simazine) and 94% (atrazine), whereas for 10 µg L^?1, the results of 73% (simazine) and 81% (atrazine) were obtained. On the other hand, ametryne showed poor recovery values (25 to 40%), probably due to a stronger interaction with MT_K, lowering the recovery values. Based on the results for atrazine and simazine, MT_K presented good features to be used as sorbent phase and for preconcentration, being easily prepared with low cost, demanding low amounts to be used for this purpose, providing fast sorption of atrazine and simazine, and with appropriate recoveries.     

A Critical Appraisal of the Experimental Data on the Molecular Structure and Spectra of Halides, Oxides, and Hydrides of the s-, d-, and f-Block Elements

Evidence for unusual shapes of simple MX(n) molecules that are not stable under normal conditions is critically appraised in this review, which assesses current knowledge of the spectra and structures of many simple binary halides, oxides, and hydrides. It emphasizes the need for more high-resolution gas-phase spectroscopic data, summarizes the current state of knowledge in many fields, and suggests key experiments that should be carried out to resolve conflicting results obtained in earlier studies.     

土壤电化学性能对铀、锶、铯分配系数的影响及机理探讨

通过静态吸附实验研究了土壤pH值、正电荷AEC值、永久负电荷CECp值等电化学性能对核素铀、锶、铯分配系数的影响,进一步结合XRD物相分析结果,对土壤滞留核素的机理进行了探讨.研究结果表明:所研究的两种土质类型中,铀的分配系数(U-Kd值)均随溶液初始pH值的减小、AEC值的增大而增大;铯、锶的分配系数与土壤的CECp值、蒙脱石和伊利石总含量呈正相关关系;Cs 、Sr2 离子势及其相应水合离子半径的差异造成土壤中铯的分配系数显著大于锶的分配系数.     

Theoretical study on the factors controlling the stability of the borate complexes of ribose, arabinose, lyxose, and xylose

Recent experimental studies suggest that complexation with borate minerals stabilizes ribose, and that the borate complex of ribose is more stable than those of related aldopentoses, that is, arabinose, lyxose, and xylose. These findings have revived the debate on the plausibility of the RNA-world theory, because they provide an explanation for the stabilization and selection of ribose in prebiotic conditions. In this paper we unravel the factors that make the ribose-borate complex the most stable one. For this purpose, we have investigated the structure and stability of the ribose-, arabinose-, lyxose-, and xylose-borate complexes using density functional theory and a continuum solvent approach. The computed results reveal that in the aldopentose-borate complexes, the electrostatic field of the borate is strong enough to change the orientation of the nearby hydroxyl groups compared to noncomplexed aldopentoses. In addition, we show that the distinct stability of the ribose-borate 2:1 complex can be attributed to 1) a strong hydrogen bond between the ribose 3-OH and one of the negatively charged borate oxygen atoms, and 2) a favorable contact between the aqueous medium and the 5-CH(2)OH group due to the space separation between the 5-CH(2)OH group and the borate anion.     

A Study on the Phosphorylation of Indole,Imidazole, Carbazole,and Phenothiazine Derivatives

Abstract

N-Heterocycles including indolecarbaldehyde, substituted benzimidazoles, and methylimidazole could be efficiently phosphorylated by diethyl chlorophosphate at room temperature in different solvents using alkali carbonate or triethylamine as the base. However, the phosphorylation of N-heterocycles with a lower reactivity at the NH function, such as carbazole and phenothiazine, could not be conducted to complete conversion under the conditions applied.     

ViscosityB-coefficients,structural entropies and heat capacities,and the effects of ions on the structure of water

The water-structural contributions to the entropies and heat capacities of hydration of over 120 ions and the viscosity B-coefficients of nearly 80 aqueous ions are tabulated and correlated. B-coefficients for many more ions are predicted from this relationship and from their dependence on ionic size and charge. The structural entropies determine a unique scale of water structure making and breaking by the ions.     

HOBt,HOOBt, HOSu与惰性氯代烷溶剂之间的反应及其对 多肽合成影响的研究

HOBt,HOSu,HOOBt是多肽合成中常用的试剂,它们常被用作羧基活化试剂和消旋抑制剂。首次发现HOBt,HOSu,HOOBt在碱的存在下可与氯代烷烃溶剂发生反应,并系统地研究了不同的反应条件对产率的影响和对多肽合成的影响。发现反应的产率与碱的用量,反应温度,反应物等因素有关,碱性越强,反应速度越快产率越高,HOBt较易反应,HOSu较为稳定,二氯甲烷易生成双取代产物,1,2-二氯乙烷易生成单代产物,所有产物均经硅胶柱层析分离纯化,共合成8个经合物并通过光谱鉴定。虽然在模型二肽BocAlaPheOCH3合成反应中检测到少量副产物的产生,但二肽的产率>82%。     

Determining the effect of centrifugal and electrical forces on the jet behaviors,the nanofiber structure,and morphology

The increasing demand for nanofibers production has led to the rapid growth of the usage of electro‐centrifugal spinning (ECS) systems especially in recent years. Besides the rapid developments, fabrication of novel fibrous materials with novel techniques is still under investigation. Polyvinylepyrrolidone (PVP) is one of the multifunctional materials, which has attracted scientific interests to be employed in a variety of advanced applications. The main objective of the present study was therefore to explore the effects of essential parameters involved in fabrication of PVP nanofibers via an ECS system. The effects of rotational speed (197‐4051 r/min) and applied voltage (0‐14 kV) on the structural and morphological properties of nanofibers were also investigated. Analyses of the scanning electron microscope (SEM) images were performed with Digimizer and SPSS16.0 software to characterize the diameter distribution of the nanofibers. The degree of crystallinity was evaluated by the X‐ray diffraction method. In order to explain the unexpected results, further investigations were performed on the motion of the jet and flow rate. The results showed that instead of nanofibers, microparticles were formed at lower voltages and rotational speeds. The increase in the applied voltage resulted in a decrease in the minimum rotational speed that is required to form continuous fluid jet. The bending instabilities were changed from whipping to spiraling at the voltages above 10 kV. This resulted in the minimum fiber diameter at a voltage between 6 and 10 kV. Moreover, the applied voltage slightly affected the degree of crystallinity. No significant change was observed in the degree of crystallinity by varying the rotational speed.     

Numerical Simulation on the Dissociation,Formation, and Recovery of Gas Hydrates on Microscale Approach

Investigations into the structures of gas hydrates, the mechanisms of formation, and dissociation with modern instruments on the experimental aspects, including Raman, X-ray, XRD, X-CT, MRI, and pore networks, and numerical analyses, including CFD, LBM, and MD, were carried out. The gas hydrate characteristics for dissociation and formation are multi-phase and multi-component complexes. Therefore, it was important to carry out a comprehensive investigation to improve the concept of mechanisms involved in microscale porous media, emphasizing micro-modeling experiments, 3D imaging, and pore network modeling. This article reviewed the studies, carried out to date, regarding conditions surrounding hydrate dissociation, hydrate formation, and hydrate recovery, especially at the pore-scale phase in numerical simulations. The purpose of visualizing pores in microscale sediments is to obtain a robust analysis to apply the gas hydrate exploitation technique. The observed parameters, including temperature, pressure, concentration, porosity, saturation rate, and permeability, etc., present an interrelationship, to achieve an accurate production process method and recovery of gas hydrates.