One-step Operation Research Articles

Comprehensive Study of the Polarization Behavior of LiFePO4 Electrodes Based on a Many-Particle Model

The unique polarization behavior of LiFePO4 electrodes was investigated using mathematical simulations with a many-particle model, which have a non-monotonic potential profile for each LiFePO4 particle, and analyzed by the active population concept. The present simulations reveal two known polarization behaviors, namely the memory effect and path dependence. Notably, a hitherto unknown polarization behavior, the so-called relaxation-induced polarization (RIP), was also identified. The memory effect requires, at a minimum, a sequential four-step operation. By comparison, RIP is triggered only by a one-step operation, namely a long rest. In effect, the polarization associated with the memory effect and RIP was caused by a reduction of the active particles in the two-phase region via relaxation during a rest. The path-dependence mechanism was attributed to kinetically inhomogeneous reactions for each particle. We further found that narrowing the particle size distribution was an effective means to reduce polarization viz. the memory effect and path dependence of LiFePO4 electrodes. However, RIP could not be suppressed by narrowing the particle size distribution. A comprehensive understanding of these polarization behaviors with our model provides a more accurate way to estimate the state of charge in Li-ion batteries with LiFePO4 electrodes.

Low-Cost Chemical-Responsive Adhesive Sensing Chips.

Chemical-responsive adhesive sensing chip is a new low-cost analytical platform that uses adhesive tape loaded with indicator reagents to detect or quantify the target analytes by directly sticking the tape to the samples of interest. The chemical-responsive adhesive sensing chips can be used with paper to analyze aqueous samples; they can also be used to detect and quantify solid, particulate, and powder analytes. The colorimetric indicators become immediately visible as the contact between the functionalized adhesives and target samples is made. The chemical-responsive adhesive sensing chip expands the capability of paper-based analytical devices to analyze solid, particulate, or powder materials via one-step operation. It is also a simpler alternative way, to the covalent chemical modification of paper, to eliminate indicator leaching from the dipstick-style paper sensors. Chemical-responsive adhesive chips can display analytical results in the form of colorimetric dot patterns, symbols, and texts, enabling clear understanding of assay results by even nonprofessional users. In this work, we demonstrate the analyses of heavy metal salts in silica powder matrix, heavy metal ions in water, and bovine serum albumin in an aqueous solution. The detection is one-step, specific, sensitive, and easy-to-operate.

Порівняльна оцінка динаміки холестатичних та цитолітичних показників і темпу декомпресії жовчних проток після одноетапних лапароскопічних та відкритих операційних втручань у хворих на холедохолітіаз, ускладнений обтураційною жовтяницею (повідомлення 2)

Мета роботи: визначити темп декомпресії жовчних проток та оцінку показників синдромів цитолізу й холестазу після одноетапних лапароскопічних і відкритих операційних втручань у пацієнтів із холедохолітіазом, ускладненим обтураційною жовтяницею.Матеріали і методи. Проведено порівняння динаміки біохімічних показників холестазу й цитолізу та темпу біліарної декомпресії у 81 хворого з холедохолітіазом, ускладненим обтураційною жовтяницею, із різним рівнем білірубіну, на 3-тю, 5-ту та 7-му добу після одноетапних лапароскопічних і відкритих операційних втручань. Темп відповіді жовтяниці на декомпресію визначали за формулою T. Shmizu і K. Yoshida в модифікації Э. И. Гальперина.Результати досліджень та їх обговорення. Встановлено, що лапароскопічна холедохолітотомія у пацієнтів із рівнем гіпербілірубінемії до 100 мкмоль/л і від 100 до 200 мкмоль/л супроводжується затяжним і помірним темпом декомпресії, що є оптимальним у післядекомпресійному періоді. У хворих із рівнем гіпербілірубінемії від 100 до 200 мкмоль/л, яким виконаний холедоходуоденоанастомоз, відмічається швидкий темп декомпресії в післяопераційному періоді, що потребує профілактичної медикаментної корекції можливого синдрому “швидкої декомпресії”.

Single step purification of bromelain from Ananas comosus pulp using a polymer/salt aqueous biphasic system

Abstract Bromelain is an important industrial proteolytic enzyme due to the wide application in food, cosmetic and therapeutic industries. There is a great demand in developing a cost-efficient method to recover bromelain from plant sources. Low interfacial tension and biocompatible aqueous biphasic system (ABS) is widely applied in various separation processes of bioproducts. Thus, recovery of bromelain from Ananas comosus (pineapple) pulp using polymer/salt ABS was attempted in this study. The ABS operating factors including polyethylene glycol (PEG) molecular weight, phase composition, pH, centrifugal force and additional of neutral salt were studied. The optimal condition for ABS recovery of bromelain from crude extract was achieved with ABS consisting of 17% (w/w) PEG 4000 and 14% (w/w) phosphate salt; centrifugal force of 6000 × g; pH of 8.0 and at 25 °C. Bromelain exhibited a high specific activity (SA) of 2.7 U and purification factor ( P F ) of 16.3 in the top phase of PEG 4000/phosphate ABS with a yield ( Y T ) of 55.6%. The findings demonstrated that ABS is a potential one-step operation in replacement to the existing methods in recovery of bromelain from plant sources.

Critical assessment: opportunities in developing semi-solid processing: aluminium, magnesium, and high-temperature alloys

Semi-solid metal processing (SSM) is a modern metal forming technology offering net-shape metal components of complex geometry in a one-step operation. The process relies on the thixotropic behaviour of metals with non-dendritic microstructures in a wide semi-solid temperature range. The beneficial effects are currently exploited in aluminium and magnesium alloys. This alternative manufacturing route to casting and forging has generated high expectations regarding high melting alloys, although no conclusive results have been achieved so far. Current studies focus on a deep understanding of the fundamental basics of alloys in the semi-solid range, e.g. rheology, microstructural evolution, and the consequences of forming, e.g. relations between process parameters, microstructure, and properties. This critical assessment aims at defining the important needs for further development of SSM, and assessing current knowledge.

Semi-solid processing of the CoCrCuFeNi high entropy alloy

High entropy alloys (HEAs) are a particularly challenging material for semi-solid processing because of the high temperatures involved. In the CoCrCuFeNi HEA examined here, the globular microstructure required for the thixoforming process was obtained by the recrystallization and partial remelting method. Based on Kazakov's criteria, a detailed characterization of the solidus-liquidus temperature range, was conducted. Semi-solid metal processing of the CoCrCuFeNi HEA was carried out at 1150°C and 1340°C, which corresponded to 15% and 35% of the liquid phase, respectively. The microstructure of the thixo-cast consisted of two face-centered cubic solid solutions: one in the form of globular grains, containing near equiatomic concentrations of Co, Cr, Fe and Ni, and the other, enriched in Cu, homogeneously distributed around grains. Depending on the process temperature, significant changes were observed in the microstructure. Compression test results of the CoCrCuFeNi HEA thixo-cast showed that yield strength was around 395MPa, while the compression strength at 40% of strain reached 1810MPa at an average hardness of 201HV. The obtained values were about 30% higher than those of the ingot material after direct casting. The melting behavior, microstructure and mechanical properties, as well as the possibility of obtaining a net-shape component in a one-step operation, make the CoCrCuFeNi HEA a promising material for thixoforming.

基于滚环扩增技术耦合切刻内切酶信号放大技术的新型超灵敏miRNA-122荧光传感器

MicroRNA-122 (miRNA-122)的异常表达与肝癌的发生、发展及转移紧密相关，发展简单、快速、高灵敏和高特异性的miRNA-122检测方法对于肝癌的早期诊断和预后评估具有非常重要的意义。本文报道了一种基于滚环扩增技术(RCA)耦合切刻内切酶信号放大(NESA)技术的新型荧光传感器并用于超灵敏和高选择性检测miRNA-122。该方法涉及了两个阶段的反应机制，第一阶段，目标物激活切刻内切酶辅助的聚合反应，用以实现目标物与次级目标物循环放大以及生成RCA引物；第二阶段，利用RCA耦合NESA反应，实现信号传导以及多重信号放大。实验结果证明，该传感器表现出对miRNA-122的非常高的灵敏度和特异性，检测下限达到3.9 aM，较之前报道的方法，灵敏度有明显的提高。另外，该方法整个过程只需一步反应，具有操作简便、成本低、检测时间短的优势。所以，所提出的基于RCA耦合NESA的荧光传感器有望建立一个简单而实用的生物传感新平台，并应用于miRNA检测以及癌症的早期诊断和预后评估。 Aberrant expression of microRNA-122 (miRNA-122) is associated with the occurrence, develop-ment and metastasis of hepatocellular carcinoma. It’s of great importance for the development of sensitive and selective method for the detection of miRNA-122 to the early diagnosis and prognosis of hepatocellular carcinoma. A novel fluorescent biosensor has been constructed for ultrasensitive and high specific detection of miRNA-122 based on rolling circle amplification (RCA) coupled with nicking endonuclease signal amplification (NESA). Our assay involves of two stages of reaction mechanism, the first stage is target-activated nicking endonuclease-assisted polymerization, which is used for the realization of the recycle amplification of target and secondary target and the produce of RCA primer. The second stage is to achieve signal transduction and multiple signal amplification by the utilization of RCA coupled with NESA. The results reveal the constructed biosensor display high sensitivity and specificity for miRNA-122 detection, and the limit of detection is as low as 3.9 aM, which is significantly improved compared to the previous methods. Moreover, the proposed method has the advantages of rapidness, low cost, simplicity with only one-step operation. Therefore, the developed RCA coupled with NESA-based fluorescent biosensor might create a simple and practical platform for the detection of miRNA and the early diagnosis and prognosis of cancer.

Gas assisted method synthesis nitrogen-doped carbon quantum dots and Hg (II) sensing

ABSTRACTNitrogen-doped fluorescent carbon quantum dots (CQDs) was prepared by gas-assisted method using cellulose as precursors under ammonia atmosphere, which not only exhibited excellent photoluminescent properties, but also showed highly selective and sensitive detection of mercury ion. The nitrogen-doped CQDs displayed excitation wavelength dependent fluorescent behavior with outstanding dispersibility. Moreover, they exhibited high tolerance to various external conditions, such as storage time, pH value, and ionic strength. The rapid detection of Hg (II) by one-step operation within 1 min and the good linear correlation between I0/I and Hg (II) concentration in the range of 10–100 nM made the nitrogen-doped CQDs a promising nanoprobe for Hg (II) detection. The detection limit of the nitrogen-doped CQDs is about 7.7 nM. Such a nanoprobe has been successfully applied for the analysis of Hg (II) in natural water samples, demonstrating excellent practical feasibility.

Fluorescent trimethyl-substituted naphthyridine as a label-free signal reporter for one-step and highly sensitive fluorescent detection of DNA in serum samples

A facile label-free sensing method is developed for the one-step and highly sensitive fluorescent detection of DNA, which couples the specific C-C mismatch bonding and fluorescent quenching property of a trimethyl-substituted naphthyridine dye (ATMND) with the exonuclease III (Exo III) assisted cascade target recycling amplification strategy. In the absence of target DNA, the DNA hairpin probe with a C-C mismatch in the stem and more than 4 bases overhung at the 3' terminus could entrap and quench the fluorescence of ATMND and resist the digestion of Exo III, thus showing a low fluorescence background. In the presence of the target, however, the hybridization event between the two protruding segments and the target triggers the digestion reaction of Exo III, recycles the initial target, and simultaneously releases both the secondary target analogue and the ATMND caged in the stem. The released initial and secondary targets take part in another cycle of digestion, thus leading to the release of a huge amount of free ATMND for signal transducing. Based on the fluorescence recovery, the as-proposed label-free fluorescent sensing strategy shows very good analytical performances towards DNA detection, such as a wide linear range from 10pM to 1μM, a low limit of detection of 6pM, good selectivity, and a facile one-step operation at room temperature. Practical sample analysis in serum samples indicates the method has good precision and accuracy, which may thus have application potentials for point-of-care screening of DNA in complex clinical and environmental samples.

Transplantation of allogenic chondrocytes with chitosan hydrogel-demineralized bone matrix hybrid scaffold to repair rabbitcartilage injury.

Cartilage tissue engineering is the hotspot of cartilage repair. The allogenic chondrocytes appear to be a promising source of seed cells in cartilage tissue engineering. In this study, we aimed to transplant allogenic chondrocytes with chitosan hydrogel (CS)-demineralized bone matrix (DBM) hybrid scaffold (CS/DBM) to repair rabbit cartilage injury with one-step operation. After the CS/DBM scaffold was successfully fabricated, it showed that the porous CS filled the large pores of DBM, which improved the distribution of seed cells in the CS/DBM scaffold. The allogenic chondrocytes at second passage were transplanted with different scaffolds to repair rabbit cartilage injury. Twenty-four weeks after surgery, the cartilage defect in the CS/DBM group was successfully filled as shown by MRI. Moreover, the histological score of CS/DBM group was significantly higher than that of the other groups. On the aspect of biomechanical property, the regenerated cartilage in the CS/DBM group were superior to those in the other groups as determined by nanoindentation. Meanwhile, no obvious inflammatory response was observed after the transplantation of allogenic chondrocytes at 24 weeks post-surgery. Furtherly, gene expression profile for cells within the repair tissue was compared with the allogenic chondrocytes before transplantation using Agilent microarray and RT-qPCR. The results showed that some genes beneficial to cartilage regeneration, such as BMP-7, HGF, and IGF-1, were upregulated one month after transplantation. Consequently, our study demonstrated that the transplantation of allogenic chondrocytes with CS/DBM scaffold successfully repaired rabbit cartilage injury with only one-step operation, thereby providing new insights into cartilage tissue engineering.

Manganese-catalyzed bicyclic annulations of imines and α,β-unsaturated esters via C−H activation

A manganese-catalyzed bicyclic annulation of imines with α,β-unsaturated esters via C–H activation is described, which provides an expedient access to fused β-lactams in one-step operation with high efficiency and good functional group tolerance. Of note, both ketimines and aldimines are amenable to this transformation. Mechanistic studies have identified a five-membered azamanganacycle as the key reaction intermediate.

A circuit design for multi-inputs stateful OR gate

The in situ logic operation on memristor memory has attracted researchers' attention. In this brief, a new circuit structure that performs a stateful OR logic operation is proposed. When our OR logic is operated in series with other logic operations (IMP, AND), only two voltages should to be changed while three voltages are necessary in the previous one-step OR logic operation. In addition, this circuit structure can be extended to multi-inputs OR operation to perfect the family of logic operations on memristive memory in nanocrossbar based networks. The proposed OR gate can enable fast logic operation, reduce the number of required memristors and the sequential steps. Through analysis and simulation, the feasibility of OR operation is demonstrated and the appropriate parameters are obtained.

Quantitative Detection of MicroRNA in One Step via Next Generation Magnetic Relaxation Switch Sensing.

One-step, quantitative and rapid detection of microRNA (miRNA) in tumor cells or tissues can provide critical information for clinical diagnosis and cancer treatment. In this work, we develop a magnetic relaxation switch sensing (MRS)-based miRNA sensor using magnetic microparticle (1 μm in diameter, MM1000)-DNA probe-magnetic nanoparticle (30 nm in diameter, MN30) conjugates (MM1000-DNA-MN30). In the presence of target miRNA, DSN enzyme selectively cleaves the DNA tether after miRNA/DNA hybridization to release MN30 and leaves the miRNA intact to lead to the declustering of more MN30 than before. In contrast to conventional MRS by measuring the change of transverse relaxation time (ΔT2) induced by the aggregation or dissociation of magnetic particles in the presence of target, we use the cleaved MN30 from conjugates as the direct readout of ΔT2, which is more sensitive and stable. This MRS-based assay allows for one-step detection of 5 fM of miR-21 in urine samples, quantification of miR-21 from 100 cancer cells, and differentiation of the expression of miR-21 in tumor and surrounding tissues. The merits of this assay, rapidity, ability for quantitation, high sensitivity, and one-step operation, ensure a promising future in diagnostic technology.

Performance investigation of thermal energy storage systems using metal hydrides adopting multi-step operation concept

The metal hydride based thermal energy storage (MHTES) technology is an attractive option for concentrating solar power. In this paper, a mathematical model was developed for MHTES systems. The charging and discharging processes of thermal energy were numerically analyzed. As shown in the simulation results, the temporal profiles of the average reacted fraction, the fluid outlet temperature and the hydrogen pressure appear to be repeated in a cyclic manner. The mean value of true temperature boost during the discharging process increases as the flowrate of the heat transfer fluid decreases. When the concept called multi-step charging/discharging operation modes was adopted instead of the conventional one-step reaction operation mode, the outlet temperature fluctuation of the heat transfer fluid of the MHTES system can be weakened. The system performance can be further improved by varying the fluid flow rate and optimizing the operation mode.

Dielectrophoretic behavior of PEGylated RNase A inside a microchannel with diamond-shaped insulating posts.

Ribonuclease A (RNase A) has proven potential as a therapeutic agent, especially in its PEGylated form. Grafting of PEG molecules to this protein yields mono-PEGylated (mono-PEG) and di-PEGylated (di-PEG) RNase A conjugates, and the unreacted protein. Mono-PEG RNase A is of great interest. The use of electrokinetic forces in microdevices represents a novel alternative to chromatographic methods to separate this specie. This work describes the dielectrophoretic behavior of the main protein products of the RNase A PEGylation inside a microchannel with insulators under direct current electric fields. This approach represents the first step in route to design micro-bioprocesses to separate PEGylated RNase A from unreacted native protein. The three proteins exhibited different dielectrophoretic behaviors. All of them experienced a marked streaming pattern at 3000 V consistent with positive dielectrophoresis. Native protein was not captured at any of the conditions tested, while mono-PEG RNase A and di-PEG RNase A were captured presumably due to positive dielectrophoresis at 4000 and 2500 V, respectively. Concentration of mono-PEG RNase A with a maximal enrichment efficiency of ≈9.6 times the feed concentration was achieved in few seconds. These findings open the possibility of designing novel devices for rapid separation, concentration, and recovery of PEGylated RNase A in a one-step operation.

A reagent-ready-on-chip microfluidic immunoassay system for rapid detection of influenza A H1N1 and H3N2 viruses

Development of effective disease screening method is the best approach for the control of infectious diseases. However, conventional screening methods require to operate in well-equipped laboratory. That makes the screening operation expensive and time-consuming. In this work, a reagent-ready-on-chip microfluidic immunoassay system was developed and rapid detection of influenza A H1N1 and H3N2 viruses was demonstrated to show its simplicity and rapidity. The microfluidic system integrated 4 single-stroke ther-mopneumatic actuators and a reaction chamber. All related reagents were pre-installed in the system and manipulated automatically for indirect immunoassay. Detection of influenza A H1N1 and H3N2 viruses based on its internal structure protein, i.e., nucleoprotein (NP), was demonstrated using the system. Result was represented by colorimetric signal in the reaction chamber. The use of thermopneumatic actuation could achieve fluid manipulation without external assistive equipment and colorimetric result could be observed directly without the need of external dedicated detector. Influenza virus screening could be completed around 1 hour with less sample volume (20 μL) and reagent volume (50 μL). The system achieved one-step operation of immunoassay. It is highly integrated and has potential to be developed to portable devices to realize rapid diagnostics in remote environment and clinics without well-equipped facility.

Three-phase solvent systems for the comprehensive separation of a wide variety of compounds fromDicranostigma leptopodumby high-speed counter-current chromatography

A three-phase solvent system was efficiently applied for high-speed counter-current chromatography to separate secondary metabolites with a wide range of hydrophobicity in Dicranostigma leptopodum. The three-phase solvent system of n-hexane/methyl tert-butyl ether/acetonitrile/0.5% triethylamine (2:2:3:2, v/v/v/v) was selected for high-speed counter-current chromatography separation. The separation was initiated by filling the column with a mixture of intermediate phase and lower phase as a stationary phase followed by elution with upper phase to separate the hydrophobic compounds. Then the mobile phase was switched to the intermediate phase to elute the moderately hydrophobic compounds, and finally the polar compounds still retained in the column were fractionated by eluting the column with the lower phase. In this research, 12 peaks were eluted out in one-step operation within 110 min, among them, eight compounds with acceptable purity were obtained and identified. The purities of β-sitosterol, protopine, allocryptopine, isocorydione, isocorydine, coptisine, berberrubine, and berberine were 94.7, 96.5, 97.9, 86.6, 98.9, 97.6, 95.7, and 92.8%, respectively.

One-step reconstruction with a 3D-printed, biomechanically evaluated custom implant after complex pelvic tumor resection

Resection of a pelvic tumor is challenging because of its complex three-dimensional (3D) anatomy and deep-seated location with nearby vital structures. The resection is technically demanding if a custom implant is used for reconstruction of the bone defect as the surgeon needs to ensure the resection margin is sufficiently wide and the orientation of intended resection planes must match that of the custom implant. We describe a novel workflow of performing a partial acetabular resection in a patient with pelvic chondrosarcoma and reconstruction with a custom pelvic implant in a one-step operation. A multi-planar bone resection was virtually planned. A computer-aided design implant that both matched the bone defect and biomechanically evaluated was prefabricated with 3D printing technology. The 3D-printed patient-specific instruments (PSIs) were used to reproduce the same planned resection. The histology of the tumor specimen showed a clear resection margin. The errors of the achieved resection and implant position were deviating (1–4 mm) from the planned. The patient could walk unaided with a good hip function. No tumor recurrence and implant loosening were noted at 11 months after surgery. The use of this novel CT-based method for surgical planning, the engineering software for implant design and validation, together with 3D printing technology for implant and PSI fabrication makes it possible to generate a personalized, biomechanically evaluated implant for accurate reconstruction after a pelvic tumor resection in a one-step operation. Further study in a larger population is needed to assess the clinical efficacy of the workflow in complex bone tumor surgery.

Optimization of the Preparation of a Minor Bioactive Chromone in Aloe barbadensis Miller Using Response Surface Methodology and its Isolation by Reversed-Phase Flash Chromatography

A bioactive chromone, 8-C-glucosyl-7-O-methyl-(S)-aloesol (compound 1), was prepared by the acid-catalyzed hydrolysis of isoaloeresin D in Aloe barbadensis Miller. The hydrolysis conditions were successfully optimized by response surface methodology (RSM). The results indicated that RSM in the present study was adequate and effective. Then, reversed-phase flash chromatography was utilized for the isolation. In a one-step operation within 45 min, 26 mg of compound 1 was isolated from 153 mg of hydrolysis product, with a purity of 99.3%. These achievements would afford sufficient amount of high pure compound for chromatographic purpose and pharmacological activity screening.

Synthesis of substituted aryl enol ethers

A facile route toward substituted aryl diarylvinyl ethers 4 is developed from CuI-mediated cross-coupling reaction of substituted phenols 2 with diarylvinyl bromides 3 in the presence of various bidentate-based ligands in DMF. Skeleton 3 is prepared by Yan’s bromomethylenation of diarylketones 1 with CHBr3–TiCl4–Mg in the co-solvent of DME and CH2Cl2. The synthetic route obtains moderate yields from the one-step operation and the key structure of 4k is confirmed by X-ray crystallographic analysis. The CADD docking experiments of 4k have been included.