核糖核酸酶A在DAB-环乙烷溶液中的活性和构象

The activity and conformation of ribonuclerse A (RNaseA) solubilized in cyclohexane via dodecylammonium butyrate(DAB) reverse micelles were investigated. The activity of RNaseA was studied using the cytidine 2’,3’ -phosphate as the substrate, and it was found that kcat increases significantly with respect to that in water attended by an increased Km•FT-IR spectra of RNaseA in reverse micellar solution were investigated as a function of w0(= [H2O]/ [DAB]), and it was noted that the structure of RNaseA became losser in reverse micelles campared to that in aqueous solution. The relation between activity and conformation was discussed.     

Effect of Butyric Acid on p53 Expression and Apoptosis in Colon Epithelial Cells in Mice after Treated with 9,10-dimethyl-1,2-benz(a)anthracene

As the most common cancer, colorectal cancer is the fourth leading cause of death among this malignancy disease. Surgery procedure with chemotherapy and radiotherapy for colorectal cancer treatment may cause unpleasant side effects. Therefore, prevention and early detection of the disease is important. Butyrate, a short chain fatty acid, has a protective effect against colon cancer by inhibiting cell proliferation and inducing apoptosis. We conduct a research to investigate the effect of butyrate as a possible agent to decreased mutant p53 gene expression.     

Effect of Ultrasonic‐assisted Preparation Methods on Structure,Morphology and Optical Properties of Nanosized Cupric Oxide

Cupric oxide is a p‐type semiconductor with a narrow band‐gap which is suitable for catalysis, electrochemical cells, field emission devices and gas sensor applications. Despite considerable efforts devoted to the preparation of the nanosized CuO, there is a lack of information about ultrasonic‐assisted (US) preparation methods. Nanosized cupric oxide was successfully prepared through different ultrasonic‐assisted (US) preparation methods. Furthermore, the influence of preparation method on the structure, morphology and optical properties of nanosized CuO has been reported. XRD patterns were identical to the single‐phase pure CuO with a monoclinic structure. The enhancement of the crystallinity and crystallite size was observed for the sample prepared through the US thermal decomposition. The absorption band of CuO nanocrystals prepared through the US liquid hydrolysis shows a clear red shift of about 40 nm compared to those obtained with other preparation methods. Our results indicated that almost spherical CuO nanoparticles with an average size of 65 nm were prepared during the US thermal decomposition, while CuO rod‐like nanostructures with an average diameter of about 16 nm were obtained via the US liquid hydrolysis method. The band gap values of nanosized CuO samples were larger than the reported value for the bulk CuO. Synthesized CuO samples by US methods with adjustable and controllable properties make the applicability of cupric oxide even more versatile.     

A highly sensitive non-enzymatic glucose sensor based on a simple two-step electrodeposition of cupric oxide (CuO) nanoparticles onto multi-walled carbon nanotube arrays

A novel, stable and highly sensitive non-enzymatic glucose (Glc) sensor was developed using vertically well-aligned multi-walled carbon nanotubes array (MWCNTs) incorporated with cupric oxide (CuO) nanoparticles. The MWCNTs array was prepared by catalytic chemical vapor deposition on a tantalum (Ta) substrate, while a simple and rapid two-step electrodeposition technique was used to prepare the CuO-MWCNTs nanocomposite. First, Cu nanoparticles were deposited onto MWCNTs at constant potential and then they were oxidized into CuO by potential cycling. The electrocatalytic activity of CuO-MWCNTs array was investigated for Glc under alkaline conditions using cyclic voltammetry and chronoamperometry. The sensor exhibited a linear response up to 3 mM of Glc and sensitivity of 2190 μA mM⁻¹ cm⁻², which is two to three orders of magnitude higher than that of most non-enzymatic Glc sensors reported in the literature. The sensor response time is less than 2 s and detection limit is 800 nM (at signal/noise = 3). When tested with human blood serum samples, the sensor exhibited high electrocatalytic activity, stability, fast response and good selectivity against common interfering species, suggesting its potential to be developed as a non-enzymatic Glc sensor.     

丁酸钠预培养对水稻花药绿苗形成的影响

对水稻花药进行了丁酸钠预培养的试验,结果表明:2mM丁酸钠24小时的预处理,可以促进小孢子的均等分裂,增加多核花粉的比例,并影响愈伤组织诱导率和愈伤组织的分化绿苗潜力,对愈伤组织分化绿苗的促进作用尤其显著。丁酸钠对愈伤组织诱导的作用,与介质的pH的值有关,pH7.0的培养基的诱导率低于pH5.8,但对分化有利。 文章讨论了丁酸钠促进愈防组织分化的可能原因,以及丁酸钠影响愈伤组织诱导和促进分化之间关系。     

铜在空气中生成碱式碳酸铜的热力学分析

从热力学角度研究了酸度、湿度、水的存在状态不同时,单质铜在空气中生成碱式碳酸铜的电动势及其自由能变。通过计算发现:在酸性条件下,p H的大小对于反应的自发性没有影响;大气中二氧化碳溶解达到饱和时,空气湿度增加,反应的自发性略微增加;相同条件下,水由气态变为液态时,反应的自发性增幅较大。     

One‐pot Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones Catalysed by Cupric Acetate under Solvent‐free Conditions

A solvent‐free synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones from aromatic aldehydes, β‐keto ester/acetyl acetone and urea catalysed by cupric acetate under thermal condition is reported as a simple and an efficient protocol. Compared with classical Biginelli reaction reported in 1893, this new method provides much improved modification in terms of yield and reaction time. The usage of milder catalyst, environmental friendly procedures and excellent yields within a very short time (5–15 min) are the advantages of the method in which the involvement of solvent‐free condition adds an edge to the method. Thus, the efficiency of the protocol enabled the rapid synthesis of 3,4‐dihydropyrimidin‐2(1H)‐one derivatives in a short duration.     

Characterization of cellulose derivatives — Relevance to sensor development

With the aim of developing a urea biosensor, several cellulose derivatives were used to coat an all-solid-state potentiometric electrode for ammonium ion determination. In this work the physical and chemical characterization of the cellulose derivatives, as well as the changes that the activation and immobilization procedures induced in the polymers, were studied.     

Highly photocatalytic activity of metallic hydroxide/titanium dioxide nanoparticles prepared via a modified wet precipitation process

Surface modification is one important approach to increase the photocatalytic activity of TiO₂. By using a modified wet precipitation process, novel M(OH)_x/TiO₂ nanoparticles were synthesized, where M(OH)_x represents ferric or cupric hydroxide. The prepared M(OH)_x/TiO₂ powders were characterized with XRD, FT-IR, BET, UV–vis DRS, and TGA, and were observed to yield high photocatalytic ability by using methyl orange (MO) as a model compound of organic pollutants to be degraded. Due to the accelerating effects of the new photocatalyst, the half-time of MO during its photocatalytic degradation at pH 6.0 over M(OH)_x/TiO₂ was decreased from 332 min for unmodified neat TiO₂ to 63 min for Fe(OH)₃/TiO₂ and 65 min for Cu(OH)₂/TiO₂, respectively. The enhancing effects of M(OH)_x/TiO₂ was further observed in a wide composition range with various M/Ti atomic ratios in the photocatalysts and in a wide pH range of the MO solution from 3 to 7. This enhancing effect is mainly attributed to the increased trapping of the photogenerated electron by the higher valence sites (Fe(III) or Cu(II)) in the hydroxide layer near the M(OH)_x/TiO₂ interface and the enriched surface hydroxyl groups which accept photogenerated holes to yield more hydroxyl radicals.     

Engineering nanostructures of CuO-based photocatalysts for water treatment: Current progress and future challenges

Nowadays, increasing extortions regarding environmental problems and energy scarcity have stuck the development and endurance of human society. The issue of inorganic and organic pollutants that exist in water from agricultural, domestic, and industrial activities has directed the development of advanced technologies to address the challenges of water scarcity efficiently. To solve this major issue, various scientists and researchers are looking for novel and effective technologies that can efficiently remove pollutants from wastewater. Nanoscale metal oxide materials have been proposed due to their distinctive size, physical and chemical properties along with promising applications. Cupric Oxide (CuO) is one of the most commonly used benchmark photocatalysts in photodegradation owing to the fact that they are cost-effective, non-toxic, and more efficient in absorption across a significant fraction of solar spectrum. In this review, we have summarized synthetic strategies of CuO fabrication, modification methods with applications for water treatment purposes. Moreover, an elaborative discussion on feasible strategies includes; binary and ternary heterojunction formation, Z-scheme based photocatalytic system, incorporation of rare earth/transition metal ions as dopants, and carbonaceous materials serving as a support system. The mechanistic insight inferring photo-induced charge separation and transfer, the functional reactive radical species involved in a photocatalytic reaction, have been successfully featured and examined. Finally, a conclusive remark regarding current studies and unresolved challenges related to CuO are put forth for future perspectives.