Convenient Steps Research Articles

Fabrication of targeted PDA-Hemin-Dox-FA nanoplatform for enhanced chemodynamic therapy synergized with chemo/photothermal therapy

Chemotherapy (CT) is widely used in clinical practice due to its simple and convenient steps, but its characteristics of systemic administration also results in a lack of targeting and a tendency to develop drug resistance, which greatly limits its therapeutic effect. In order to overcome these problems, a PDA-Hemin-Dox-FA (PHDF) nanoplatform was constructed in this work for the combined treatment of tumors. Firstly, hemin was introduced into the self-polymerization of dopamine to synthesize PDA-Hmein (PH) nanoparticles. Then, the chemotherapy drug doxorubicin (Dox) and targeted folic acid (FA) were loaded onto PH surfaces through Schiff base and amide bonds respectively to construct PHDF. When PHDF enters the tumor cells through the targeting guidance of FA, the acidic microenvironment of the tumor will induce the cleavage of the Schiff base bond in PHDF to release Dox. The presence of hemin makes PHDF have high Fenton-like activity, which generate large amount of·OH to perform chemodynamic therapy (CDT). Driven by near infrared laser light, PHDF exhibited wonderful photo-thermal conversion performance which not only brings excellent photo-thermal therapy (PTT) effect, but also promotes the uptake of Dox and the production of·OH, leading to enhanced CT and CDT efficacy. Taken together, the PHDF nanoplatform constructed in this study shows good CT/PTT/CDT combined therapy against tumor cells and it also provides a promising alternative for the combination therapy of tumors.

Single-colour, visible light activation and excitation of the luminescence of a ‘switch-on’ dye and enhancement by silver nanoparticles

We synthesized a fluorogenic methylated dihydrofluorescein derivative in two convenient steps from commercial fluorescein. This species can switch to the corresponding oxidized form upon visible-light illumination at an activating wavelength of 455 nm, where the photoinduced transformation culminates in the activation (‘switch on’) of the fluorescence, which can be observed by exciting the photoproduct at the same wavelength of activation. Thus, a single wavelength can be used to simultaneously activate and excite fluorescence. Mechanistic investigations suggest that singlet oxygen does not contribute to the formation of the fluorescent oxidation product. The single-colour activation/excitation mode of this model structure can effectively mimic a pseudo two-colour system and can find broad application in the development of photonic materials operated with simple optical setups. The activated fluorescence can be concomitantly enhanced by triangular silver nanoparticles according to the principles of metal-enhanced fluorescence (MEF).

Chiral Quaternary Ammoniums Derived from Dehydroabietylamine: Synthesis and Application to Alkynylation of Isatin Derivatives Catalyzed by Silver

Abietic acid and its derivatives have broadly been used in fine chemicals and are renewable resources. Its inherent chiral rigid tricyclic phenanthrene skeleton is unique. Its utilities in asymmetric catalysis remain to be explored. A series new amide-type chiral quaternary ammoniums bearing dehydroabietylamine were designed, and prepared by two convenient steps. Acylation of dehydroabietylamine with bromoacetyl chloride afforded amide holding bromoacetyl group in higher yields using triethyl amine as base. Subsequent quaternization reaction gave the desired amide-type chiral quaternary ammoniums. The new chiral quaternary ammoniums can be used as phase-transfer catalyst (PTC) for the transition metal-catalysed alkynylation of isatin derivatives.

Correction pen as a hydrophobic/lipophobic barrier plotter integrated with paper-based chips and a mini UV-torch to implement all-in-one device for determination of carbazochrome

The design of a cheap, simple, and handy sensing system for rapid quantitation of pharmaceuticals becomes mandatory to ease drug development procedures, quality control, health care, etc. This work describes a simple, innovative, and easily manufactured paper-based device using a correction pen as a plotter for hydrophobic/lipophobic barriers and graphene quantum dots for recognition and quantification of the hemostatic drug carbazochrome, via fluorescence turn-off mechanism mediated by the inner filter effect. A smartphone-based all-in-one device fitted with an inexpensive 365 nm flashlight as a UV light source and a free image processing software was developed for rapid and reliable interpretation of the fluorescence change from the paper-based device upon introduction of the drug. The simple and convenient steps permit the analysis of many samples in a very short time. The smartphone-based all-in-one device featured excellent sensitivity for carbazochrome with a limit of detection equals to 12 ng/detection zone and good %recovery (100.0 ± 0.4). The reliability of the device was ascertained by favorable statistical comparison with the analogous optimized conventional fluorimetry method and a reference HPLC method. The device has been successfully applied for versatile quantitation of carbazochrome in tablets and on manufacturing equipment surfaces with excellent recoveries. The device offers many green aspects that definitely assist the implementation of the sustainability concept to analytical laboratories. The cost-efficiency, reliability, and ease of fabrication as well as the greenness and user friendship qualify the device for wide application in low-income communities.

Impact of seasonal rainfall trend and its variability on crop production in rainshadow districts of Chhattisgarh: A case study in Kawardha district

In this research work we studied the impact of seasonal rainfall trend and its variability on production of major crops at Kawardha district of Chhattisgarh state. For this study, long term rainfall data (1962-2015) and crop data (2000-2014) were used. The mean annual rainfall of 983.8 mm was recorded in Kawardha with coefficient of variation of 17 %. The coefficient of variation was lowest during monsoon season like the CV during July and August is less than 40 % where as it is more than 50 % but less than 60 % in June and September months. In Kawardha district, mean annual rainfall of 983.8 mm was observed out of which south- west monsoon received 854.7 mm with coefficient of variation 18 percent. During south-west monsoon period mean of 46 days was observed with coefficient of variation of 19 percent. Rest of seasons received mean rainy days of less than 6 with coefficient of variation more than 70 percent. Rest of seasons received the mean rainfall of less than 70 mm with coefficient of variation of more than 90 percent. The CV of less than 100 percent was found during the season of north-east monsoon period. The seasonal rainfall pattern in this area is similar to annual rainfall as more than 90 per cent of annual rainfall is received during kharif season. There is a statistically non significant trend of seasonal rainfall has been found in this district but a significant rainfall trend was found in the month of August at 5 % level of significance. The area, production and productivity of all the selected crops are showing a significant increasing trend with some exception in Maize (decreasing trend of area), Soyabean(productivity trend is not significant) and arhar (non significant value).The main crop production of the district was concentrated on this seasonal rainfall pattern. So, water harvesting and storage is more convenient steps towards this.

Improvement in the performance of SOI-MESFETs by T-shaped oxide part at channel region: DC and RF characteristics

In this paper, a new structure for silicon on insulator (SOI) metal semiconductor field effect transistor (MESFET) is proposed. This new structure improves DC and RF characteristics of the device by embedding a region of hafnium oxide which is shaped like a reversed T letter in the channel region. This structure is named SOI-MESFET with T-Shaped oxide part (T-SOP). Hafnium oxide region increases the breakdown voltage of the device due to its higher critical electric field in comparison with silicon used in the conventional structure (C-SOI MESFET). The breakdown voltage of the conventional structure is 14 V while it raises to 19.5 V in proposed structure. Furthermore, placing this region in the channel, increases the operating frequencies of the device due to the modification in capacitances. Studying the maximum output power density shows that the proposed structure causes 31.5% improvement compared with the C-SOI MESFET. To improve the device performance, dimensions of the oxide region have been optimized and the more optimum performance achieved by varying the dimensions and finding the most suitable values. Due to the mentioned superiorities of the proposed structure over its conventional counterpart, it can be said that the proposed structure has the capability to be used as a reliable alternative for C-SOI MESFET in high voltage and high frequency applications. Also, from fabrication point of view, a fabrication process flow for T-SOP structure is proposed which shows convenient steps to develop this device.

Grafting Polymers from Poly(2,6-dimethyl-1,4-phenylene oxide) as New Thermoplastics

Graft polymers with poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) as backbones are successfully prepared via two convenient steps. The utilization of semiflexible PPO as backbones offers unique properties for the graft polymers. Thermal, rheological, and phase behaviors of these new graft polymers are well controlled via the precise design of architectural parameters. The disordered microphase separation in melt state and the proper composition of side grafts provide the ease of thermal processing for these graft polymers. The graft density shows impact on the relaxation and mechanical properties of the thermoplastics. This work shows the possibility to use lots of semiflexible engineering polymers as backbones to construct new thermoplastics.

Arthropod Deterrents from Artemisia Pallens (Davana Oil) Components

Davanone, a key sesquiterpene component of davana oil, has been synthesized in five convenient steps. Oxygenated sesquiterpenes have been linked to insect deterrent properties. Based on initial screening of davana oil, davanone and its hydroxy precursors have been generated and are being evaluated as arthropod deterrents against disease vectors.

ChemInform Abstract: Total Synthesis of ent‐(‐)‐Azonazine Using a Biomimetic Direct Oxidative Cyclization and Structural Reassignment of Natural Product.

Abstract A biomimetic approach has been investigated and developed for the total synthesis of azonazine, an unusual marine natural cyclopeptide containing a rigid transannular 10-membered ring. A hypervalent iodine-mediated direct oxidative cyclization was successfully developed and applied to construct the highly strained core, which was the key step in the first total synthesis of ent-(−)-azonazine. Based on the physical evidences of synthesized diastereomer and enantiomer of azonazine, both the relative and absolute configurations of the natural product were revised. Two fluorinated azonazine derivatives were also synthesized in short convenient steps utilizing the same intermediate in this work. The established total synthesis opens a potential opportunity to study the structure–activity relationship of natural azonazine.

Total synthesis of ent-(−)-azonazine using a biomimetic direct oxidative cyclization and structural reassignment of natural product

A biomimetic approach has been investigated and developed for the total synthesis of azonazine, an unusual marine natural cyclopeptide containing a rigid transannular 10-membered ring. A hypervalent iodine-mediated direct oxidative cyclization was successfully developed and applied to construct the highly strained core, which was the key step in the first total synthesis of ent-(−)-azonazine. Based on the physical evidences of synthesized diastereomer and enantiomer of azonazine, both the relative and absolute configurations of the natural product were revised. Two fluorinated azonazine derivatives were also synthesized in short convenient steps utilizing the same intermediate in this work. The established total synthesis opens a potential opportunity to study the structure–activity relationship of natural azonazine.

Object-oriented software for evaluating measurement uncertainty

An earlier publication (Hall 2006 Metrologia 43 L56–61) introduced the notion of an uncertain number that can be used in data processing to represent quantity estimates with associated uncertainty. The approach can be automated, allowing data processing algorithms to be decomposed into convenient steps, so that complicated measurement procedures can be handled. This paper illustrates the uncertain-number approach using several simple measurement scenarios and two different software tools. One is an extension library for Microsoft Excel®. The other is a special-purpose calculator using the Python programming language.

Facile Syntheses of Histamine- and Imidazole-4-propionic Acid–Derived Room-Temperature Ionic Liquids

We report synthesis of histamine- and imidazole-4-propionic acid–based ionic liquids containing a variety of alkyl and aryl groups placed at the two different positions of the constituent imidazole ring in convenient steps in good yields.

A straightforward and convenient pathway for the synthesis of functional bismacrocyclic ligands

The synthesis of a novel DO3A-based bismacrocyclic ligand is reported. The synthetic pathway involved a series of simple and convenient steps, which can easily provide the desired product in larger quantities than produced in current synthetic procedures. This method enables the facile preparation of binuclear macrocyclic complexes which can be used in MRI, as well as other molecular imaging modalities.

On Modular Products Development

Quite a few investigations have been carried out on modularity in product development. However, the presence of various perspectives, representations, and different problems hamper a holistic comprehension of modular products development (MPD) or modularity. This article is developed to give a deeper understanding of MPD. An evolutionary history of modularity, consisting of five stages, is introduced. The relationships among the benefits of modularity, such as cost-reduction, diversity, and innovation ability are then discussed in detail along with their relationships to related research issues. The implementation aspect of MPD is explained in three tiers: central, mediate, and peripheral. It shows that former theories and methods can hardly meet the needs of MPD application in real practice, and that metrics and measurement cannot take into account the degree of modularity, and cost-reduction becomes unclear and more complex. Based on this, a new powerful approach with 15 convenient steps for MPD is presented and compared with former reported research results. Also, recommendations for future research have been suggested.

An Expedient Entry to Fused [1,2,5]-Triazepine Derivatives: Extension to Fused [1,2,5]-Oxadiazine Derivatives, a New Class of Seven-Membered Heterocycles

This document describes an efficient synthesis of fused indole containing tricyclic [1,2,5]-triazepine derivatives from 2-cyanomethyl indole in two simple and convenient steps. This new methodology allows us to synthesize a variety of substituted [1,2,5]-triazepine derivatives in excellent yields. Further exploration of this methodology using 2-cyanomethyl indole and hydroxylamine directed us to access a new class of seven-membered fused [1,2,5]-ox- adiazine derivatives in good to excellent yields.

Thiophene Backbone Amide Linkers, a New Class of Easily Prepared and Highly Acid-Labile Linkers for Solid-Phase Synthesis

Solid-phase synthesis is of tremendous importance for small-molecule and biopolymer synthesis. Linkers (handles) that release amide-containing products after completion of solid-phase synthesis are widely used. Here we present a new class of highly acid-labile backbone amide linkers (BAL handles) based on 3,4-ethylenedioxythiophene (EDOT), which we have termed T-BAL. These thiophene linkers are synthesized in three convenient steps from commercially available EDOT. In the linker design, the spacer was introduced to the EDOT core either via a carbon-carbon bond or via a thioether linkage. Introduction of the spacer via a C-C bond was performed by a chemoselective Negishi coupling without transient protection of the aldehyde group to provide the T-BAL1 handle. Introduction via a thioether linkage was performed by a facile nucleophilic aromatic substitution between the brominated EDOT aldehyde and unprotected mercapto acids to provide T-BAL2 and T-BAL3 handles. The minimal use of protecting groups gave the corresponding linker molecules in few synthetic steps and in good yields. After anchoring of the linker to a polymeric support, introduction of the first amino acid was achieved by reductive amination, giving a secondary amine. A following acylation of the secondary amine with a symmetrical amino acid anhydride resulted in a backbone amide linkage between the handle and the growing substrate (e.g., peptide chain). After solid-phase synthesis, the substrates could be released from the resin by either low acid conditions using 1% TFA in CH2Cl2 or high acid conditions such as 50% TFA in CH2Cl2. Peptide thioesters could be released from the T-BAL1 handle under very mild conditions using aqueous acetic acid. Tert-butyl based protecting groups, tert-butyl esters, tert-butyl ethers, and Boc groups, as well as dimethyl acetals were relatively stable to these mild conditions for release of the peptides.

New Reagent for Convenient Access to the α,β‐UnsaturatedN‐Methoxy‐N‐methyl‐amide Functionality by a Synthesis Based on the Julia Olefination Protocol

AbstractA new reagent for the synthesis of the α,β‐unsaturatedN‐methoxy‐N‐methyl‐amide structural unit has been developed. 2‐(Benzo[d]thiazol‐2‐ylsulfonyl)‐N‐methoxy‐N‐methylacetamide, a crystalline solid with an indefinite shelf life that can be easily prepared in two convenient steps from 2‐chloro‐N‐methoxy‐N‐methylacetamide, reacted with a variety of aldehydes under Julia conditions to furnish the α,β‐unsaturatedN‐methoxy‐N‐methyl‐amide functionality. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Two dialkoxynaphthalene aldehydes as backbone amide linkers for solid-phase synthesis.

Two new solid-phase handles for backbone amide anchoring based on regioisomeric dialkoxynaphthalene aldehydes (NALdehydes) were synthesized in five convenient steps from the corresponding commercially available dihydroxynaphthalenes. The two NALdehydes were coupled to an aminomethyl polystyrene support, the first monomer attached by efficient reductive amination, and the secondary amine acylated to form naphthalene amide linker (NAL-1 and NAL-2) anchoring. After on-resin synthesis, release of peptides was effected with TFA/H(2)O (95:5), TFA/DCM (50:50), or low TFA concentrations. The properties of the NAL handles were evaluated in the solid-phase synthesis of a series of peptides, in which NAL-2 showed the best cleavage properties.

Rotation about an inclined axis: Three dimensional matrices for reconstructing paleomagnetic and structural data

We derive matrices for calculating the three-dimensional finite rotation that restores a rigid block to its pre-displacement attitude. To use this technique an initial horizontal bedding is assumed, and the following orientations must be known: the expected field orientation of magnetization, the situ orientation of the paleomagnetic vector and the bedding normal. The restoring rotation is decomposed into two convenient steps, represented by rotation matrices, such that they restore the in situ paleomagnetic vector together with the tilted bedding normal to their original orientation. These auxiliary rotations combine algebraically to a single finite rotation from which an inclined axis and amount of rotation arc obtained. We demonstrate this method by reconstructing a distinct section of the Mount Sedom salt diapir (Dead Sea Rift Valley, Israel). Here, the conventional tilt correction that brings the bedding to horizontal fails to position the paleomagnetic vector in its expected orientation. Only a rotation of 125 ° about an axis which plunges 50 ° southward can restore both bedding and magnetization to their expected orientations.

Vinyl Carbanions. Part 36.. Synthesis of 3‐deoxy‐D‐manno‐2‐octulosonic acid (KDO) and derivatives

AbstractThe β‐C‐lithiated acrylamide 3A has been proven to be an ideal pyruvate β‐carbanion equivalent useful in a highly diastereoselective KDO synthesis. The starting material 3 was prepared from pyruvate diethyl acetal in four convenient steps. Direct lithiation with 2 equiv. of LDA generated the dilithiated species 3A quantitatively. Reaction with 2,3:4,5‐di‐O‐isopropylidene‐D‐arabinose (11) was highly D‐manno‐selective. The product 12 was obtained readily from the reaction mixture via crystallization. Ring closure to the butenolide 13, subsequent PhS‐group removal with Bu3SnH and pyridinium bromide, and hydrogenolytic debenzylation afforded the known butenolide 19; this KDO precursor gives KDO in two convenient steps. Butenolide 19 was also transformed via two high‐yielding steps into the 4,5:7,8‐di‐O‐cyclohexylidene‐KDO derivative 22, a valuable starting material for KDO α‐glycoside syntheses.