Two Series of Synthetic Territrem B Analogues and their Biological Activities

Two series of territrem B analogues (6, 11) were designed and synthesized from jujubogenin 2. Compound llc inhibited AChE with the ratio of 70% at 10^-4 mol/L. Compounds5a, 5b, 6a and lib showed moderate cytotoxicity on cultured KB cells at 10^-6 mol]L.Compounds 5c and 6b alleviated injury arising from oxygen-glucose deprivation (OGD).     

In situ Synthesis of Oligonucleotides on Plasma Treated Polypropylene Microporous Membrane

Polypropylene microporous membranes were treated with plasma in a mixture of N2 and H2 (1:2 in volume). Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and ultra-violet (UV) spectra demonstrated the success of grafting amino groups. The density of the polar amino groups on the membrane surface is about 0.59 μmol/cm^2. The as-treated membranes were successively applied to the in situ synthesis of oligonucleotides and an average coupling yield was more than 98%. The surface feature of the treated membrane is suggested to be responsible for its advantage over a glass slide.     

Studies on Synthesis of a Cycloheptapeptide and Effects of Different Metal Ions on the Cyclization

ＩｎｔｒｏｄｕｃｔｉｏｎＣｙｃｌｉｃｐｅｐｔｉｄｅｓ ,ｗｈｉｃｈａｒｅｃｏｎｓｔｒａｉｎｅｄｃｏｎｆｏｒｍａ ｔｉｏｎａｌｌｙａｎｄｍｏｒｅｒｅｓｉｓｔａｎｔｔｏｐｒｏｔｅａｓｅｄｉｇｅｓｔｉｏｎｓｔｈａｎｔｈｅｉｒｌｉｎｅａｒｐｒｅｃｕｒｓｏｒｓ ,ｈａｖｅｂｅｅｎｏｆｇｒｅａｔｉｎｔｅｒｅｓｔａｓｓｙｎｔｈｅｔｉｃｔａｒｇｅｔｓｂｏｔｈａｓｐｏｔｅｎｔｉａｌｄｒｕｇｌｅａｄｓａｎｄａｓｍｏｄｅｌｓｆｏｒｃｏｎ ｆｏｒｍａｔｉｏｎａｌａｎａｌｙｓｉｓ .1 4 Ｃｕｒｒｅｎｔｍｅｔｈｏｄｓｆｏｒｓｙｎｔ…     

Microcalorimetric Study of the Biological Effects of Zn^＋ on Bacillus thuringiensis Growth

A microcalorimetric technique was used to investigate the influence of Zn^2 on the growth metabolism of Bacillus thuringiensis .LKB-2277 Bioactivity Monitor was employed to obtain the power-time curves,from which the maximum peak-heat output power(Pmax) in the log phase,the growth rate constants(k), the inhibitory ratios(I) ,the generational time(tG) and the total heat effect (Qtotal) in 23 h for the growth metabolism of Bacillus thuringiensis at 28℃ can be evaluated,The results indicate that the concentration of Zn^2 affects its growth obviously,Low concentration (0-50μg/mL) of Zn^2 promotes the growth of Bacillus thuringiensis while high concentration (50-500μg/mL) of Zn^2 inhibits its growth .When the concentration reached up to 600μg/mL,it can not grow at all.     

Synthesis and Biological Evaluation of Pyranone Analogues of Territrem B

As a highly selective and potent acetylcholinesterase(AChE)inhibitor,territrem B wasisolated by Ling et al.from a strain of Aspergillus terreus in19791,2.Zhao et alreported mimic preparation of territrem B analogues from triterpenoids and found thatthe enone moiety and aromatic ring played important roles in their syntheticcompounds3,4.To further detect essential pharmacophors for AChE inhibitors,wesimplified the A/B ring system of territrem B and synthesized a number of pyranonepharmacop…     

Synthetic,Structural and Biological Studies on Cyclic 3′,5′-Nucleotide Analogs and Derivatives

Abstract

Cyclic 3′,5′-monophosphates (with the general formula I) of 5-alkylcytidines, 5-alkyl-2′-deoxyuridines, 5-halocytidines, 5-halouridines and 5-halo- and 5-(trif luoromethyl)-2′-deoxy-uridine have been synthesized and evaluated for their antiviral and antitumor properties.     

Toxics or Lures? Biological and Behavioral Effects of Plant Essential Oils on Tephritidae Fruit Flies

The family Tephritidae (Diptera) includes species that are highly invasive and harmful to crops. Due to globalization, international trade, and human displacement, their spread is continuously increasing. Unfortunately, the control of tephritid flies is still closely linked to the use of synthetic insecticides, which are responsible for detrimental effects on the environment and human health. Recently, research is looking for alternative and more eco-friendly tools to be adopted in Integrated Pest Management (IPM) programs. In this regard, essential oils (EOs) and their main compounds represent a promising alternative to chemical insecticides. EOs are made up of phytoconstituents formed from the secondary metabolism of many plants and can act as attractants or toxics, depending on the dose. Because of this unique characteristic, EOs and their main constituents are promising tools that can be used both in Sterile Insect Technique (SIT) programs and in the “lure and kill” technique, exploiting the attractiveness of the product in the former case and its toxicity in the latter. In this article, current knowledge on the biological and behavioral effects of EOs and their main constituents on tephritid fruit flies is reviewed, mainly focusing on species belonging to the Anastrepha, Bactrocera, Ceratitis, and Zeugodacus genera. The mechanisms of action of EOs, their real-world applications, and challenges related to their use in IPM are critically discussed.     

Preparation and Application of Polymyxin B Affinity Membrane Cartridge

lmRooucroN~ns~~biolOgical~inhumanasweIlasmanyanirnaI~whenadminbepematheIly.TheremodofetrintrinudshaSbogodyemPhastaedtriingtDthewedeefoPmedsOfbjOfeqbelengiweringinrootwers.Amongthemedsforendfornrernodngandminiminng,theaffintyadsopen,whichtakeSplaceunderamildcondthonandodatringidsedon,meconsideredtOb6aboudsfOrtheuseinbiofOgbelsamples[11.Inour~oustyWork,anewteChniquenameIyrnembrane8ffintychromaboraphywasedopeforth6eodnmI.bohaamntych~raPhy.Wbichmhinesthedstwafmembfan.SePatoandamnty~.~tOb…     

Synthesis of Tetracycline Analogues and Test of Their Affinity on Synthetic Hydroxyapatite

To develop bone target drugs is an attractive field for increasing the potency and selectivity of these drugs in the treatment of osteoporosis and Pagets disease etc. As known, after systematic administration tetracycline can be distributed in bone and bind to hydroxyapatite with high affinity1. Thus we tried to use tetracycline as a bone targeted carrier. However, tetracycline is less stable, and its complex structure bring much difficulty in the coupling reaction and purification of the p…     

Microcalorimetric Study of the Biological Effects of Zn~(2+) on Bacillus thuringiensis Growth

ＩｎｔｒｏｄｕｃｔｉｏｎＣａｌｏｒｉｍｅｔｒｙｈａｓｂｅｅｎｕｓｅｄｉｎｍｏｎｉｔｏｒｉｎｇｃｅｌｌｕｌａｒｍｅｔａｂｏｌｉｓｍｂｙｍｅａｎｓｏｆｈｅａｔｍｅａｓｕｒｅｍｅｎｔｓ ,ｅｓｐｅｃｉａｌｌｙｉｎｓｔｕｄｙｉｎｇｍｅｔａｂｏｌｉｓｍｉｎｃｅｌｌｓａｎｄｗｈｏｌｅｏｒｇａｎｉｓｍ .1,2 Ｍｉ ｃｒｏｃａｌｏｒｉｍｅｔｒｙｉｓａｌｓｏｕｓｅｄｉｎｍｅａｓｕｒｉｎｇｔｈｅｅｆｆｅｃｔｓｏｆｖａｒ ｉｏｕｓｓｕｂｓｔａｎｃｅｓａｎｄｃｕｌｔｕｒｅｃｏｎｄｉｔｉｏｎｓｏｎｍｅｔａｂｏｌｉｓｍ .Ｍｉｌｅ…     

Synthetic Studies on Spirolides A and B: Formation of the Upper Carbon Framework Based on a Lewis Acid Template-Catalyzed Diels–Alder Reaction

The upper fragment of spirolides A and B, which are marine phycotoxins that exhibit strong antagonistic activities on nicotinic acetylcholine receptors, was constructed. The functionalized cyclohexene in spirolides was stereoselectively synthesized from the bicyclic lactone, which could be readily accessed by the Lewis acid template-catalyzed asymmetric Diels–Alder reaction of the pentadienol and methyl acrylate.     

Effects of ZrO_2 on the Microstructure of a Mica Glass-ceramic

1 INTRODUCTION Glass-ceramic technology is based on the controlled nucleation and crystallization of glass, and glass-ceramics have several advantages over the conventional powder-processed ceramics. In addition to the easy flexibility of formation in t…     

Synthetic studies on cytotoxic macrolides cruentarens A and B: stereoselective synthesis of the C8–C19 segment of cruentarens A and B

A stereoselective synthesis of the C₈–C₁₉ segment of cruentarens A and B, cytotoxic natural products, has been accomplished. The key steps involve a stereoselective radical cyclization, stereospecific methylation of a γ, δ-epoxy acrylate, nucleophilic epoxide ring opening and a cis-Wittig olefination.     

Effects of nitren extraction on a dissolving pulp and influence on cellulose dissolution in NaOH–water

A commercial dissolving pulp was treated with aqueous solutions containing 3, 5 and 7 % of an organometalic complex (nitren) with the aim to selectively extract xylan and study its impact on the conventional physical–chemical properties of the pulp. The influence of these treatments on the pulp dissolution in a moderate solvent (8 % NaOH aqueous solution) was assessed by measuring the dissolution yields and the dissolution mechanisms. The results of this study show that nitren treatment has the effect of removing a large part of the xylan present in a dissolving pulp. It is also removing mannans and most important, it is influencing cellulose in two ways, (1) extracting it with more intensity when the nitren concentration increases, and (2) decreasing its mean molecular mass, also more evident with nitren concentration increase. The nitren extractions are favourable for the dissolution in cold NaOH–water, being more effective with higher concentrations. This chemical modification of the fiber surface leads to the disassembly of the primary wall. This allows an easier access of the NaOH reagent to regions not accessible on the initial fibres, which with the decrease of the cellulose molecular weight allows an easier dissolution and gives different dissolution mechanisms.     

Effects of binders and graphite on the sensitivity of ε-HNIW

In order to optimize formulations of PBX based on Hexanitrohexaazaisowurtzitane (HNIW) and meet the application in mixed explosive, the mold powder of HNIW coated by varied binders was obtained by aqueous suspension technology. Several particle sizes of graphite were added as additive with a 0.5 % mass ratio. The experiment results showed that fluorine resin (FPM) was better than polyurethane and cis-butadiene rubber when the mass percentage of binders was fixed at 4 %. The characteristic height of HNIW/FPM (96/4) mold powder was at 28 cm (2.5 kg hammer), while that of the neat HNIW was at 15 cm merely, and the friction explosion probability fell from 100 to 70 %. The addition of flake graphite with proper grain size would reduce the mechanical sensitivity of HNIW and improved the fluxion property of HNIW-based mold powders. The thermal stability characteristic of HNIW FPM (96/4) and HNIW/FPM/G (96/4/0.5) were studied by thermogravimetric analysis (TG) at 10 °C min^?1, the peak decomposition temperatures were at 251 and 250 °C, which were closed to that of neat HNIW(249 °C) and also identified superior thermal stability of compound.     

Thin Layer Chromatography of Synthetic Dyes on Antimonic Acid and on Admixture of Antimonic Acid and Silica Gel ‘G’ in a Mixed Solvent System

Abstract

Thin layer chromatography of synthetic dyes have been performed on antimonic acid and on admixture of antimonic acid and silica gel ‘G’ in a mixed solvent system i. e. Butanol: Acetic acid: water (25:5:10). The separation potential of antimonic acid and silica gel ‘G’ has been explored. Several important separations of closely related dyes have been achieved as a result of such studies.     

Design and Synthesis of Muramyl Dipeptide Cyclic Analogue

A new conformationalloy restricted cyclic analogue of muramyl dipeptide was designed and manually synthesized by our “Meshed-Bag Gathered-Bunch” method with a combination of Fmoc,ally and N-1-(4,4-dimethyl-2,6-dioxocyclo-hexylidene) ethyl chemical protection strategy.     

Stepwise Replication of a Tröger's Base Analogue

Redox-controlled covalent templating and macrocyclization underlie a novel scheme for stepwise exponential self-replication. This process has been demonstrated by using Tr?ger's base analogue 1 as the template.     

Structural Effects on Defects and Growth in Crystals of Urea

1INTRODUCTIONThecrystalofureaisanonlinearopticalmaterial(13andcanbeprepareanopticalparameterocillator(OPO)element[2).LargeperfectcrystalshavebeengrownbysO.lutionmethod[3i,v!'athez-directionrestrictedgrowth..thed,thedirectionwiththehighestgrowthspeed.However,nodetailedinformationwasgivenondislocationsandstrainfeaturesrevealedbyX-raydiffractiontopography"'.Weconcentrateonstudyofthestructuraleffectsonthedefectiveformationandgrowthmorphology.foeureacrystalcrystallizesinthete-tragonalsystem"…     

Syntheses and Biological Activities of Novel Benzotriazole Compounds Containing a Thioamide Group

IntroductionTriazoles(including benzotriazole)and their deri-vatives represent one of the most active classes of com-pounds possessing a wide spectrum of biological activi-ties.During the past several years,considerable evi-dence has been accumulated to d…