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Abstract: A new improvement based on outlet fractionation and feedback has been developed for simulated moving bed (SMB) chromatography. In this contribution, this fractionation and feedback SMB (FF-SMB) concept is extended to the general scenario which integrates a simultaneous fractionation of both outlet streams. A model-based optimization approach, previously adopted to investigate single fractionation, is extended to consider this flexible fractionation policy. Quantitative optimization studies based on a specific separation problem reveal that the double fractionation is the most efficient operating scheme in terms of maximum feed throughput, while the two existing single fractionation modes discussed in our previous study are also significantly superior to the conventional SMB operation. The advantages of the double fractionation extension are further demonstrated in terms of several more detailed performance criteria. In order to evaluate the applicability of the fractionation and feedback modification, the effect of product purity, adsorption selectivity, column efficiency and column number on the relative potential of FF-SMB over SMB is examined. [Copyright &y& Elsevier]

Abstract: A novel modification of simulated moving bed (SMB) technology, referred to as fractionation and feedback SMB (FF-SMB), has been introduced recently. This concept is based on fractionating one or both outlet streams and feeding the off-spec fractions back into the unit alternatingly with the original feed mixture. In this paper, the optimization problem of FF-SMB realizing one outlet fractionation is considered. A mathematical optimization framework based on a detailed process model is presented which allows to evaluate quantitatively the potential of this operating scheme. Detailed optimization studies have been carried out for a difficult separation characterized by small selectivity and low column efficiency. The results reveal that the proposed fractionation and feedback regime can be significantly superior to the classical SMB chromatography, in terms of both feed throughput and desorbent consumption. The effect of the feeding sequence on the performance of FF-SMB is also examined. [Copyright &y& Elsevier]

In order to design more reasonable and effective acid deposition control policies, the critical load function (CLF) was established and a two-dimensional critical load function figure was drawn based on the steady-state mass balance (SMB) method. The figure could be divided into five different regions: critical load region (non-control region), S deposition control region, N deposition control region, S and N deposition selective control region and S and N deposition simultaneous control region. According to the region into which the deposition point fell, we could choose the corresponding control approach. With further consideration of high base cation deposition (BCdep) in China, a three-dimensional critical load function surface could be drawn by taking BCdep as a variable. As a case study, critical loads of sulfur and nitrogen for the lateritic red earth in Guangzhou were calculated with current deposition data, vegetation data and soil data obtained by field sampling and laboratory analysis. Results showed that the current deposition point fell into the critical load region and a 75% reduction in BCdep caused the deposition point falling into S deposition control region, which indicated the importance of controlling sulfur deposition. While taking the critical load of nutrient nitrogen into account, the current deposition point fell into N deposition control region and with the reduction of BCdep, the deposition point entered S and N deposition simultaneous control region, which meant sulfur and nitrogen deposition should be controlled at the same time. [ABSTRACT FROM AUTHOR]

Two enantiomers that constitute a racemate have different activities when employed as pharmaceuticals. Consequently, the pharmaceutical industry has been forced to market pure enantiomers instead of the racemic mixture. Simulated moving bed (SMB) is a chromatographic process that operates continuously without losing the enantiomeric purity of outlet streams from SMB. The present work describes the enantioseparation of mandelic acid in a labscale SMB unit. Chiral stationary phase was made by packing Kromasil TBB (O,O′-bis(4-tert-buylbenzoyl) -N,N′-diallyl-L-tartar diamid) gel into empty columns. The outlet streams were sampled and analyzed by an analytical HPLC. Analysis indicated that purity values range from 82% to 94% according to the change of extract stream flow rate. [ABSTRACT FROM AUTHOR]

The article describes a procedure for separating chiral mixtures in real simulated moving bed (SMB) technology and presents a new flexible unit, the FlexSMB-LSRE. An extended SMB separation methodology was applied which considers different unit design particularities and a measures to compensate either dead volumes switching time asymmetries or delay in order to be able to separate a racemic mixture of guaifenesin with product purities higher than 98% and productivity of 23 g enantiomer/dm³CPS day in the lab-scale.

Abstract: Open-loop simulated moving bed (SMB) has been used for immobilized metal affinity chromatographic (IMAC) purification of his-tagged β-glucosidase expressed in E. coli. A simplified approach based on an optimized single column protocol is used to design the open-loop SMB. A set of columns in the SMB represent one step in the chromatographic cycle i.e. there will be one set each of columns for load, wash, elution etc within the SMB. Only the wash and elution are operated with columns in sequence. The β-glucosidase was purified to almost single band purity with a purification factor of 15 and a recovery of 91%. SMB-performance showed reduced buffer consumption, higher purification fold, a better yield and higher productivity. [Copyright &y& Elsevier]

The design of a simulated moving bed (SMB) process relies on valid thermodynamic predictions of multicomponent adsorption built up from accurate binary adsorption equilibrium data. Experimental adsorption equilibria of binary mixtures constituted by propane, propylene, isobutane and 1-butene on 13X zeolite were determined using breakthrough experiments at 373 K and 150 kPa. In addition, these binary adsorption experiments allow to confirm the choice of isobutane as an interesting desorbent for the separation of propane-propylene by SMB, since it has an intermediate selectivity between the two species to separate. Various prediction models are available in the literature but only a few of them have both physical and thermodynamical consistency. The ideal adsorbed solution theory (IAST), the thermodynamically consistent extended Toth model (TCET), and the physically-consistent extended Toth isotherm (PCET) were used to predict binary adsorption equilibria from pure component adsorption isotherms parameters. The PCET model was found suitable for representing the adsorption equilibrium of the different hydrocarbon mixtures with a reasonably good accuracy. [ABSTRACT FROM AUTHOR]

The evaluation of unmeasurable quantities is an issue faced in several fields. One example is in the production of pharmaceuticals, in which, typically, isomer properties related to different effects are found: one enantiomer may kill while the other may cure. Thus, strict quality control is necessary in this field, which requires accurate, reliable and frequent measurements of the system. However, the measurement of the main quality properties associated with the production of some pharmaceuticals has a low frequency. Consequently, in addition to safety-related issues, financial losses are also related to these low frequency of measurements, as the product can easily run towards an out of spec production. In this scenario, the present work proposes a novel Deep Artificial Intelligence structure, which has an intrinsic (Nonlinear Output Error) NOE structure, associated with a (Nonlinear AutoRegressive with Exogenous input) NARX predictor, to be used as an online soft sensor in order to provide information about the main properties of a Simulated Moving Bed chromatographic unit, commonly used in the production of pharmaceuticals, in order to mitigate the low frequency of measurement associated with this unit. The proposed structure is here called Improved Quasi-Virtual Analyzer. The model can adapt itself as the process evolves, having the possibility of online learning through measurements obtained in the laboratory periodically. The proposed structure was tested in a software-in-the-loop scenario and compared with a more traditional alternative. These tests showed a robust capacity of the Improved Quasi-Virtual Analyzer to provide reliable predictions in real-time, as well as to outperform the traditional artificial network structure. • An Improved Quasi-Virtual Online Analyser based on Deep Neural Networks and Offline Measurements is presented. • A hybrid structure is proposed, composed of NARX and NOE predictors. • Deep Learning is used to provide online learning through offline measurements. • The Improved Quasi-Virtual Online Analyser showed a robust capacity to provide reliable prediction in real-time. [ABSTRACT FROM AUTHOR]

Monoclonal antibodies (mAbs) are among the most important therapeutic proteins for the treatment of cancer. They also find wide application in the field of diagnostics. The market for mAbs was US$ 5.4 billion in 2002 and is expected to triple by 2010 (1). MAbs are mainly produced in cell culture and purified by chromatography. Apart from the mAb, the downstream processing is confronted with a multitude of impurities from the upstream process. Some of these impurities bind strongly to the chromatographic stationary phase and can only be removed by separate cleaning solutions. Depending on the type of media used, e.g. affinity or ion exchange, differing cleaning regimes may have to be applied. In addition, sanitization is required to prevent microbial contamination. Both steps are closely tied to the mAb production step and need to be repeated in regular intervals. In this work, the impact of irreversible impurity adsorption on the separation performance is investigated experimentally; first for a batch column and then for a continuous chromatographic process. At first, the retention time of a model substance is established as a suitable measure to describe the degree of irreversible adsorption. The impact of the presence and the absence of cleaning-in-place (CIP) on the retention time of the model substance is demonstrated. Since the issue of column cleaning is particularly important if processes are operated in continuous mode, in the second part of this work the introduction of a CIP step in the continuous multicolumn countercurrent solvent gradient purification (MCSGP) process is investigated. The process purifies a mAb from a cell culture supernatant that also contains irreversibly adsorbing impurities—or impurities that desorb in a later cycle of the process as a contamination. Following the same approach as for the batch experiments, the MCSGP process is operated in the presence and the absence of CIP in order to track prospective changes of the process performance caused by changes in the product retention time. Instead of the model substance, a cell culture supernatant, providing a real case impurity profile in an industrial application is used for the process. Although an impact of the product retention time change on the process yield is not observed it is shown that CIP is required for a stable long-term operation in terms of purity and system pressure drop. With the introduction of a CIP step the process was successfully operated for 9000 min (6 days) without interruption. [ABSTRACT FROM AUTHOR]

Abstract: HBII-52 is a human brain-specific C/D box snoRNA that potentially regulates the editing and/or alternative splicing of the serotonin receptor. Forty-two nearly identical copies of the HBII-52 gene are located immediately downstream of the SNRPN protein-coding gene in an imprinted locus associated with Prader–Willi syndrome. Other eutherian mammals, with genomic assemblies covering the corresponding locus, also have multiple orthologous copies of HBII-52. The SNRPB gene, which is known to have given rise to SNRPN through gene duplication, expresses a C/D box snoRNA, SNORD119, from its fifth intron. Here we show that, despite the fact that they lie in different positions relative to the orthologous SNRPB/SNRPN coding sequences, there are significant sequence similarities between SNORD119 and HBII-52, including the antisense element and the stem-forming regions. By analysing these snoRNAs in marsupial and eutherian mammal genomes, we reconstruct the likely evolutionary history of the HBII-52 cluster and SNORD119 and suggest that they have evolved from a common ancestor. [Copyright &y& Elsevier]

Copyright of Revista Daena: International Journal of Good Conscience is the property of Spenta University Mexico and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chromatography and SMB processes were studied to isolate only the intermediate retained component from ternary mixtures. The separation of ternary phenol and amino acid mixtures was simulated with Aspen Chromatography®. Simulation results for the phenol system with 10 µm packing showed that recycled center-cut chromatography usually produced the highest purity compared to cascades with two 4-zone SMBs and a 2-zone SMB/chromatography. For the amino acid mixture at ΔPmax=1.0 bar and purity-recovery index=95%, the recycled cascade of two 4-zone SMBs had approximately a 25% larger productivity compared to the simpler recycled center-cut chromatography. [ABSTRACT FROM AUTHOR]

Simulated moving bed (SMB) chromatography is very useful for the separation of binary systems such as chiral compounds. Because loxoprofen racemate has four enantiomers owing to its two chiral centers, to gain pure enantiomer it is impossible with only one step. To apply enrichment of loxoprofen using SMB, extract and raffinate should be separated as a binary mixture. In order to enrich loxoprofen racemate as binary mixture among four mixtures and to characterize its enantiomer, we performed experiments with two types of columns. When TBB® column was used as CSP, the mixture of (1′R,2S) and (1′S,2S) forms was eluted as a raffinate and that of (1′R,2R) and (1′S,2R) forms was discharged as a extract under linear adsorption isotherm range. When the feed flow rates were 0.1 and 0.3 mL/min, purities of raffinate and extract were 98 and 95%, respectively. In this case, productivity of raffinate was 7.81 g/h·g-CSP and that of extract was 6.95 g/h·g-CSP [ABSTRACT FROM AUTHOR]

A gradient SMB model is used to analyze the separation performance of proteins in a step-wise salt gradient ion-exchange simulated moving bed (IE-SMB) for the nonlinear adsorption equilibrium isotherms. The strategy of the selection of salt gradient in IE-SMB chromatography is discussed based on the adsorption equilibrium isotherms of both BSA and myoglobin on Q-Sepharose FF anion exchanger in the pH 8 Tris buffer. The separation region is used to select the flow rates in the salt gradient IE-SMB chromatography for the separation of proteins. The separation region is calculated by the gradient SMB model where both the mass transfer resistance in the ion exchangers and axial liquid dispersion in columns are taken into account. Some strategies are suggested for the selections of salt gradient and flow rates in the IE-SMB chromatography with open loop configuration for two cases: (a) binary separation of proteins with the requirement of the complete recovery from extract stream and raffinate stream; and (b) protein purification from a stream with some impurities. [ABSTRACT FROM AUTHOR]

Simulated moving bed (SMB) processes are widely used in sugar, petrochemical, and pharmaceutical industries. However, systematic optimization of SMB, especially finding the optimal zone configuration including the standard and modified non-standard configurations, is still a challenging problem. This paper proposes a simultaneous, fully discretized approach with an SMB superstructure using an interior-point solver. To find the optimal structure, two superstructures are analyzed to develop standard and non-standard configurations. In case studies of the linear and bi-Langmuir isotherms, optimal zone configurations have been successfully obtained without introducing discrete variables. Finally, the effect of the number of columns on the optimal throughput is investigated. [Copyright &y& Elsevier]

Abstract: We propose an HTS bulk bearing flywheel energy system (FWES) with rotor shaft stabilization system using feed-back control of the armature currents of the motor-generator. In the proposed system the rotor shift has a pivot bearing at one end of the shaft and an HTS bulk bearing (SMB) at the other end. The fluctuation of the rotor shaft with SMB is damped by feed-back control of the armature currents of the motor-generator sensing the position of the rotor shaft. The method has merits that the fluctuations are damped without active control magnet bearings and extra devices which may deteriorate the energy storage efficiency and need additional costs. The principle of the method was demonstrated by an experiment using a model permanent magnet motor. [Copyright &y& Elsevier]

Smooth muscle myosin heavy chains occur in 2 isoforms, SMA (slow) and SMB (fast). We hypothesized that the SMB isoform is predominant in the faster-contracting rat vena cava compared to thoracic aorta. We compared the time to half maximal contraction in response to a maximal concentration of endothelin-1 (ET-1; 100 nM), potassium chloride (KCl; 100 mM) and norepinephrine (NE; 10 μM). The time to half maximal contraction was shorter in the vena cava compared to aorta (aorta: ET-1 = 235.8 ± 13.8 s, KCl = 140.0 ± 33.3 s, NE = 19.8 ± 2.7 s; vena cava: ET-1 = 121.8 ± 15.6 s, KCl = 49.5 ± 6.7 s, NE = 9.0 ± 3.3 s). Reverse-transcription polymerase chain reaction supported the greater expression of SMB in the vena cava compared to aorta. SMB was expressed to a greater extent than SMA in the vessel wall of the vena cava. Western analysis determined that expression of SMB, relative to total smooth muscle myosin heavy chains, was 12.5 ± 4.9-fold higher in the vena cava compared to aorta, while SMA was 4.9 ± 1.2-fold higher in the aorta than vena cava. Thus, the SMB isoform is the predominant form expressed in rat veins, providing one possible mechanism for the faster response of veins to vasoconstrictors. Copyright © 2007 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Although most patients with spinal muscular atrophy (SMA) are homozygous for deletion of the SMN1 gene, some patients bear one SMN1 copy with a subtle mutation. Detection of such an intragenic mutation may be helpful not only in confirming diagnosis but also in elucidating functional domains of the SMN protein. In this study, we identified a novel mutation in SMN1 of two Japanese patients with type I SMA. DHPLC and sequencing analysis revealed that they harbored a point mutation in SMN1 exon 3, 275G > C, leading to tryptophan-to-serine substitution at amino acid 92 (W92S) at the Nterminal of SMN Tudor domain. In-vitro protein binding assays showed that the mutation severely reduced interaction of the domain with SmB protein and fibrillarin, suggesting that it impairs the critical function of SMN. In conclusion, we reported here that a novel mutation, W92S, in the Tudor domain affects the interaction of SMN with the target proteins. [ABSTRACT FROM AUTHOR]

In this work, performances of simulated moving bed (SMB) chromatography and its modification Varicol are evaluated numerically and experimentally for the separation of racemic pindolol on -acid glycoprotein (AGP) stationary phase. The equilibrium dispersive model together with experimentally determined bi-Langmuir isotherm is used to describe the dynamic behavior of SMB and Varicol processes. A shortcut design strategy based on triangle theory is presented in order to find the complete separation region for this nonlinear system. The reliability of the mathematical model and the efficiency of the design strategy have been verified experimentally using a laboratory-scale SMB set-up. Good agreement between the experimental and simulation results is obtained. The influences of the column configuration and variation of isotherm parameters on SMB performances are also discussed. [Copyright &y& Elsevier]

A new simulated moving bed (SMB) operation technique is introduced, the outlet streams swing (OSS), based on the dynamic collection of fronts from the equivalent true moving bed (TMB). This new assumption improves the product outlet purities, when compared with the classic operating mode, as a consequence of an increased separation between collection fronts and the contaminating ones. The strategy is dynamic and discontinuous, a collection front expansion is performed in zone 1 and/or 4, obtained by the violation of the classic respective design constraints during a first step and contraction during the second step using at least the classic design operating parameter for zones 1 and 4. Another non-conventional technique, the MultiFeed (MF) SMB operation, is simulated and analyzed here as a solo technique as well as a powerful modelling technique for the particular case of inner sections Varicol® (only the zones 2 and 3 have variable number of columns). [ABSTRACT FROM AUTHOR]

A simple unmixed reservoir was developed for the one column chromatograph with recycle analogous to an SMB (Analog) to replace mixed tanks or a complicated unmixed reservoir. Separation of the 1,1' bi-2-naphthol enantiomers was studied. In the linear range the purity index (PI) of the Analog with mixed tanks is 87.5, PI = 94.8 for the unmixed reservoir Analog, and PI = 96.9 for the SMB. SMB scaling rules, extended to Analogs, are used to increase the product purities of the unmixed reservoir Analog to match SMB purities but with lower productivity. Then productivity is increased at constant purity by operating at the maximum allowable pressure drop (15 bar) in each step. After scaling, the unmixed reservoir Analog's productivity was higher than the productivity of a standard SMB (one recycle pump) at the same purities (PI = 96.9), and the mixed tanks Analog's productivity was 3.5 times higher than the standard SMB, but with a significantly lower purity. [ABSTRACT FROM AUTHOR]

Abstract: The selectivity of size-exclusion chromatography (SEC) can be modified by adding non-ionic micelles to the mobile phase. Surfactant-aided size-exclusion chromatography (SASEC) can therefore very well be performed in a gradient mode on an SMB, as is reported in this paper. A method has been developed for correctly positioning a micellar gradient over an SMB. The method is applied for size-exclusion chromatography with the non-ionic surfactant C12E23 as gradient forming solute, and demonstrated by applying it to a relevant chromatographic protein separation problem. [Copyright &y& Elsevier]

Abstract: In this paper, a state observer is proposed for the reconstruction of the concentration profiles in a simulated moving bed. The approach is based on a simple Luenberger-like correction term. The observer is used under the assumption that the flow rates are constant during each switching period. The matrix gain of the correction term may then be re-computed at the beginning of each switching period corresponding to flow rates being changed by the controller. Validating simulations are proposed to assess the efficiency of the proposed profile reconstruction and its robustness against uncertainties on modelling parameters. Comparisons are also done with open-loop simulation based-observer in order to strengthen the relevance of the correction term. [Copyright &y& Elsevier]

Abstract: Simulated moving bed (SMB) technology is a continuous chromatographic technique proven to have many advantages compared to conventional batch chromatography, such as: raised productivity and product concentration, reduced buffer consumption as well as more efficient use of raw material. In this study a 20 column SMB process for the separation of lactoperoxidase and lactoferrin from whey protein concentrate (WPC) was developed. A simplified approach with data from a single column experiment was used when designing the process. The SMB process data were compared to a theoretical scale-up of the breakthrough experiment reflecting the same 20 column set-up run in non-moving bed mode. The outcome of the comparison is a 48% raise in productivity, a 4.3 times decrease in buffer consumption, 6.5 times raise in target protein concentration with a raw material utilization which is slightly better for the SMB process. [Copyright &y& Elsevier]

Analogs, recycled chromatography systems that mimic SMBs, for both a cascade of two four‐zone SMBs and five‐zone SMBs performing ternary separations are designed and analyzed. The basic Analog consists of one column and several mixed tanks equal to the number of columns in the mimicked SMB. Analogs with mixed tanks give lower purities than the SMBs because of mixing in the tanks. For example, the five‐zone SMB with one column per zone achieved a purity index (PI) of 88.3, while the Analog with five mixed tanks has a PI of 83.4. If the tanks are divided into smaller tanks the purity improves, and for the Analog to be the five‐zone SMB using 10 tanks the PI was 85.4. Analogs with a single unmixed reservoir were also designed for a cascade of two four‐zone SMBs with one column per zone. This reservoir reduces the mixing and improves the separation. For example, a cascade of two four‐SMBs with one column per zone achieved a PI of 86.7; the Analog to this SMB with 8 mixed tanks achieved a PI of 82.9, while the Analog with an unmixed reservoir achieved a PI of 84.6. [ABSTRACT FROM AUTHOR]

Abstract: Polymeric capillaries made from polyether ether ketone (PEEK) or ethylene-tetrafluoroethylene copolymer (Tefzel) are considered as highly inert and chemically resistant materials used as standard equipment in HPLC and simulated moving bed (SMB) applications. During several racemate separations using a SMB unit equipped with these tubes a formation of micro-holes was observed. All separations had in common that a high content of an alkane was used in the mobile phase. The patterns of damage and possible reasons causing the leakages of the capillaries are discussed. Polymeric tubing had to be replaced by stainless steel capillaries for the enantiomer separations in order to ensure safety of workers, GMP status of products and control leakages. [Copyright &y& Elsevier]

Abstract: Sample solubility in the mobile phase and enantioselectivity are key factors in chiral preparative chromatography. In the search for a high throughput process for production of pure enantiomers, the rational design of the mobile phase and the selection of a suitable chiral stationary phase (CSP) are essential. However, one may sometimes be faced with the incompatibility between the CSP and the preferential eluent for sample solubility. Such a limitation may be circumvented by using an immobilized CSP such as CHIRALPAK® IA. In this manuscript, the chiral separation of a Ca-sensitizing drug (EMD 53986) is optimized on CHIRALPAK® IA in terms of sample solubility, enantioselectivity and preparative productivity. The approaches for method optimization and the impact of sample solubility on productivity are discussed. The preparative potential of CHIRALPAK® IA is also demonstrated. [Copyright &y& Elsevier]

Simulated Moving Bed or SMB chromatography is a continuous adsorption technique that increases throughput, purity and yield relative to batch chromatography. SMB utilizes a series of columns with periodically moving inlet and outlet ports. This technique has been applied for the production of petrochemicals and sugars, and to a limited extent, pharmaceuticals. The recent surge in SMB research has led to various novel SMB schemes or configurations. This review presents a survey and comparison of SMB schemes and equipment, specifically SMB valve designs, which are needed to implement the various schemes. Illustrated examples include SMBs with three, four, five, eight, nine, or twelve zones, Varicol scheme, Japan Organo process, fast startup and shutdown, and online decoupled regeneration. The SMB valve designs reviewed are classified into central and distributed valves designs, which include two-way-valve designs and rotary-valve designs. We also present a novel SMB design, the Versatile SMB or V-SMB, which can implement all the novel schemes by using a one-rotary-valve-per-column design. Select-Trapping valves are used to interrupt the stream between the columns and to act as a junction that allows streams to be partially or totally added or removed, or to flow through to the next column. The streams can also be redirected to another SMB zone. Compared to other SMB valve designs, the V-SMB:(1) can be configured for open-loop, multi-zone and zone bypass operation;(2) does not require a carousel for column rotation;(3) does not contribute to product contamination;(4) allows independent port switchings, which is required for certain schemes;(5) allows additional columns to be added easily; and,(6) requires only constant speed pumps. The V-SMB has successfully purified enantiomers, sugars, organic acids, an antibiotic, and biosynthetic human insulin. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Chemical Engineering is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents an innovative bearing design for linear and rotatory superconducting magnetic bearings. In order to evaluate the bearings characteristics, two test benches have been set up and several tests for a temperature range from 40 K to 80 K have been performed. A description of the test facilities and the results are presented. Further the realization of the necessary activation process for SMB is discussed and a solution is given, which makes the use of SMB possible for applications that don't allow any displacement of the suspended part of the machinery. [ABSTRACT FROM AUTHOR]

The semantic environment description (SMB) is a structured method used for evaluating the impression of an architectural environment. The SMB-method measures the impression with eight factors: pleasantness, complexity, unity, potency, social status, enclosedness, affection and originality. The SMB-method is also a useful tool for measuring the impression of a vehicle interior since the method is easy to administrate, has high reliability and validity, is easily adaptable for cross cultural comparisons and provides useful knowledge for design, engineering and marketing. The purpose of the present study was to more deeply investigate the feasibility of the SMB method for measuring the impression of vehicle interiors and to compare customers' and Volvo employees' assessments. The present study confirms that the SMB-method is easy to administer. The method is useful, even though it is not optimized for vehicle environments. If complemented with qualitative techniques the SMB-method provides more interesting results. Volvo employees and customers assessed the vehicle interiors slightly different. Thus it is recommended to use customer's assessments to aquire useful results. [ABSTRACT FROM AUTHOR]

One-piece ring Nd–Fe–B high performance permanent magnets are successfully produced for the radial type superconductive magnetic bearing (SMB) of 10 kW h class flywheel system. The inhomogeneity of magnetic flux density achieved is quite small and is less then ±1% in the whole ring magnet with the size of OD 160.0 × ID 126.8 × 12.25 mm, where OD is outer diameter and ID is inner diameter. Levitation force density of 63,000 and 76,000 Pa was obtained for this SMB under 3 and 6 mm displacement at 77 K, respectively. Measured rotational loss was less than 0.14 W at zero initial load with 6000 rpm speed, which value is remarkably low compared with the previous data. [Copyright &y& Elsevier]

Rhizosphere microbes are critical to the initial transfer and transformation of root carbon inputs to the soil but our understanding of the activity of these organisms remains constrained by their limited culturability. In this study we combined isotopic 13C tracer and molecular approaches to measure the incorporation of recently assimilated plant C into soil microbial RNA and DNA pools as a means to determine the turnover of the ‘active’ rhizosphere community. This required the development of a method for the extraction, purification and preparation of small-sample soil DNA and RNA (<5 μg C) for isotope analysis. Soil, plant and respired CO2 samples were collected from a 13CO2 pulse-chase experiment at intervals for 20 days post-labelling. The peak of 13C release in soil/root respired CO2 came between 5 and 48 h after 13CO2 pulse-labelling and was followed by a secondary peak of soil heterotroph 13C respiration after 136 h. Results showed that both soil DNA and RNA rapidly incorporated recent photosynthate with greatest 13C found in the ‘active’ microbial RNA fraction reflecting higher rates of microbial RNA turnover. The dilution rate of the pulse derived 13C in RNA-C was used to estimate a microbial RNA turnover of approximately 20% day−1 with a 15–20 day residence time for photosynthate derived 13C in the RNA pool. The findings of this work confirm the rapid transfer of photosynthate C inputs through soil microorganisms to the atmosphere as CO2 and the potential of the biomolecular-isotope tracer approach in soil C research. [Copyright &y& Elsevier]

In the frame of a project on the development of a reduced-scale-levitating rail-vehicle prototype, the performance of two different permanent magnets have been tested in linear bearings using YBa2Cu3O7−y bulk superconductors. The levitation forces, the stiffness and the vibration damping have been measured using two different rail assemblies: one mounted with NdFeB magnets and another with ferrite ones. The levitation force of the NdFeB rail is more than one order of magnitude larger than that of the ferrite one. The stiffness of those linear bearing and the vibration damping were measured for several cooling heights from the rail. The stiffness increases with the decrease of the cooling height and is larger in the NdFeB rail. The vibration damping is rather low in both systems. Finally, we conclude that the NdFeB magnets are the most suitable for applications on linear levitating bearings. [Copyright &y& Elsevier]

The possibility of applying SMB chromatography for the separation of 2,6-DMN and 2,7-DMN was investigated by numerical simulation based on the single column chromatography experimental data. It was found that 2,6-DMN could be separated from 2,7-DMN in the ODS-modified silica gel by using methanol and water as the mobile phase. A systematic method of obtaining model parameters for the SMB simulation from single column chromatography experiments was presented. The adsorption isotherms of 2,6-DMN and 2,7-DMN were obtained by the pulse method. The mass transfer kinetics was very fast, indicating that the mobile phase and the stationary phase are very close to equilibrium for both 2,6-DMN and 2,7-DMN. SMB simulation was performed by using the model parameters. Pure 2,6-DMN and 2,7-DMN can be obtained by selecting suitable operating conditions, indicating that SMB chromatography can be employed to separate 2,6-DMN and 2,7-DMN. The influence of operating parameters (feed flow rates, raffinate flow rate, and switch time) was also investigated to recommend the optimum operating conditions. [ABSTRACT FROM AUTHOR]

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This work presents the results of an in-depth study of managers of 98 small and medium-sized businesses (SMB) in Peru, in the shoe, chemical products, automobile parts and plastic products sectors. The results give insight into the administrative characteristics of these companies (personnel management, production, marketing, accounting and finance). In addition, it provides an overview of the businesses& managers expected performance in each business, and of the actual performance in each sector. [ABSTRACT FROM PUBLISHER]

Woody cells generate lignocellulosic biomass, which is a promising sustainable bioresource for wide industrial applications. Woody cell differentiation in vascular plants, including the model plant poplar (Populus trichocarpa), is regulated by a set of NAC family transcription factors, the VASCULAR-RELATED NAC-DOMAIN (VND), NAC SECONDARY CELL WALL THICKENING PROMOTING FACTOR (NST)/SND, and SOMBRERO (SMB) (VNS)-related proteins, but the precise contributions of each VNS protein to wood quality are unknown. Here, we performed a detailed functional analysis of the poplar SMB-type VNS proteins PtVNS13-PtVNS16. PtVNS13-PtVNS16 were preferentially expressed in the roots of young poplar plantlets, similar to the Arabidopsis thalianaSMB gene. PtVNS13 and PtVNS14, as well as the NST-type PtVNS11, suppressed the abnormal root cap phenotype of the Arabidopsis sombrero-3 mutant, whereas the VND-type PtVNS07 gene did not, suggesting a functional gap between SMB- or NST-type VNS proteins and VND-type VNS proteins. Overexpressing PtVNS13-PtVNS16 in Arabidopsis seedlings and poplar leaves induced ectopic xylem-vessel-like cells with secondary wall deposition, and a transient expression assay showed that PtVNS13-16 transactivated woody-cell-related genes. Interestingly, although any VNS protein rescued the pendant stem phenotype of the Arabidopsis nst1-1 nst3-1 mutant, the resulting inflorescence stems exhibited distinct cell wall properties: poplar VNS genes generated woody cell walls with higher enzymatic saccharification efficiencies compared with Arabidopsis VNS genes. Together, our data reveal clear functional diversity among VNS proteins in woody cell differentiation and demonstrate a novel VNS-based strategy for modifying woody cell wall properties toward enhanced utilization of woody biomass., (© The Author(s) 2021. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)