Low Regeneration Efficiency Research Articles

Research on faradic capacitive deionization regeneration method for absorption air conditioning system

The development of renewable energy driven air conditioning system is of importance for curbing the CO2 emission. Absorption air conditioning systems could be a good choice but for its low regeneration efficiency. Capacitive deionization (CDI) regeneration method has been proposed to improve the efficiency of absorption system by eliminating the energy waste in the traditional thermal regeneration method. The core part of CDI is the electrode normally made from porous carbon materials, which often suffers from low charge storage capacity and co-ion repulsion. On the purpose of performance optimization, this paper proposes a hybrid deionization (HCDI) regeneration method by fabricating the electrode from Faraday materials. Experimental research has been made on the regeneration capacity of the prepared electrodes. Investigation has been conducted on the performance of the HCDI method based absorption system. The influence of different parameters has been revealed. Compared with the porous carbon electrode, the Faraday electrode has raised the charge efficiency by 20%, and raised both the regeneration capacity and overall performance by 40%. Under optimized working conditions, the COP of the HCDI based absorption system has reached 3.51 in the experiments, which shows great potential for future application.

Electrochemical Oxidation of Organic Compounds and the Creation of Metal Oxide Nanocomposites

Electrochemical regeneration suffers from low regeneration efficiency due to side reactions like oxygen evolution, as well as oxidation of the adsorbent. Utilizing the solution cast method, we three alternative strategies for producing Cr2O3 nanoparticle-laden polyvinyl alcohol (PVA) solid polymer films. The peaks in the FTIR spectrum at molecular vibration and chemical bonding frequencies indicate that Cr2O3 is present in the PVA polymer structure.

Research advancements on nerve guide conduits for nerve injury repair.

Peripheral nerve injury (PNI) is one of the most serious causes of disability and loss of work capacity of younger individuals. Although PNS has a certain degree of regeneration, there are still challenges like disordered growth, neuroma formation, and incomplete regeneration. Regarding the management of PNI, conventional methods such as surgery, pharmacotherapy, and rehabilitative therapy. Treatment strategies vary depending on the severity of the injury. While for the long nerve defect, autologous nerve grafting is commonly recognized as the preferred surgical approach. Nevertheless, due to lack of donor sources, neurological deficits and the low regeneration efficiency of grafted nerves, nerve guide conduits (NGCs) are recognized as a future promising technology in recent years. This review provides a comprehensive overview of current treatments for PNI, and discusses NGCs from different perspectives, such as material, design, fabrication process, and composite function.

Considerations in engineering viral vectors for genome editing in plants

Plant viruses have been engineered to express proteins and induce gene silencing for decades. Recently, plant viruses have also been used to deliver components into plant cells for genome editing, a technique called virus-induced genome editing (VIGE). Although more than a dozen plant viruses have been engineered into VIGE vectors and VIGE has been successfully accomplished in some plant species, application of VIGE to crops that are difficult to tissue culture and/or have low regeneration efficiency is still tough. This paper discusses factors to consider for an ideal VIGE vector, including insertion capacity for foreign DNA, vertical transmission ability, expression level of the target gene, stability of foreign DNA insertion, and biosafety. We also proposed a step-by-step schedule for excavating the suitable viral vector for VIGE.

Enhancing wheat regeneration and genetic transformation through overexpression of TaLAX1

In the realm of genetically transformed crops, the process of plant regeneration holds utmost significance. However, the low regeneration efficiency of several wheat varieties currently restricts the use of genetic transformation for gene functional analysis and improved crop production. This research explores overexpression of TaLAX PANICLE1 (TaLAX1), which markedly enhances regeneration efficiency, thereby boosting genetic transformation and genome editing in wheat. Particularly noteworthy is the substantial increase in regeneration efficiency of common wheat varieties previously regarded as recalcitrant to genetic transformation. Our study shows that increased expression of TaGROWTH-REGULATING FACTOR (TaGRF) genes, alongside that of their co-factor, TaGRF-INTERACTING FACTOR 1 (TaGIF1), enhances cytokinin accumulation and auxin response, which may play pivotal roles in the improved regeneration and transformation of TaLAX1-overexpressing wheat plants. Overexpression of TaLAX1 homologs also significantly increases the regeneration efficiency of maize and soybean, suggesting that both monocot and dicot crops can benefit from this enhancement. Our findings shed light on a gene that enhances wheat genetic transformation and elucidate molecular mechanisms that potentially underlie wheat regeneration.

Improvement in CO2 Capture of Polyamine with Micro-Interfacial System.

Polyamines have emerged as a promising class of CO2 absorbents due to their remarkable sequestration capacity. However, their potential industrial application as aqueous absorbents is significantly hindered by a low regeneration efficiency and high energy consumption. To address these issues, this study investigates the use of triethylenetetramine (TETA) and ethylene glycol (EG) to develop a nonaqueous absorbent. The incorporation of EG enhances absorption performance and reduces the regeneration energy needed for TETA, whereas the high viscosity of the absorbent impedes absorption rate, amine efficiency, and regeneration efficiency. In order to enhance CO2 capture, micron-sized reaction units (SiO2@TETA-EG) were developed by encapsulating TETA solution with nanosilica. The SiO2@TETA-EG composite exhibits a large specific surface area (99 m2/g), with a porous shell structure and improved fluidity, which effectively counteracts the negative effects caused by high viscosity. Notably, SiO2@TETA-EG indicates a noticeably higher apparent rate constant of 4.29 min-1 at 323.2 K compared to the TETA-EG solution. Furthermore, SiO2@TETA-EG displays a 28.4% boost in regeneration efficiency while maintaining favorable stability in pore size and shape after regeneration.

Constructing a CdS QDs/silica gel composite with high photosensitivity and prolonged recyclable operability for enhanced visible-light-driven NADH regeneration

Visible-light-driven nicotinamide adenine dinucleotide (NADH) regeneration is one of the most effective measures, and cadmium sulfide (CdS) materials are typically used as low-cost photocatalysts. The CdS photocatalysts, however, still suffer from low regeneration efficiency and poor cycle stability. In this work, the CdS quantum dots (QDs) less than 10 nm embedded onto silica gel (CdS QDs/Silica gel) were constructed for visible-light-driven NADH regeneration by a successive ionic layer adsorption reaction and ball milling method. Results demonstrate that the photosensitivity of the CdS QDs/Silica gel composite was 31 times higher than that of the bulk CdS. Moreover, the conduction band (CB) edge of the CdS QDs/Silica gel composite is −1.34 eV, which is more negative 0.5 eV than that of the bulk CdS. The obtained CdS QDs/Silica gel composites showed the highest NADH regeneration yields of 68.8% under visible-light (LED, 420 nm) illumination and can be reused for over 40 cycles. Finally, the bioactivity of NADH toward enzyme catalysis is further confirmed by the hydrogenation of benzaldehyde to benzyl alcohol catalyzed with an alcohol dehydrogenase as enzyme catalysis.

Research on solar-driven interfacial evaporation regeneration performance of different solutions for liquid desiccant cooling system

Liquid desiccant cooling systems (LDCS) are promising air-conditioning systems for energy conservation in buildings. However, their development is limited by significant energy waste and low regeneration efficiency. To improve, a solar-driven interfacial evaporation (SDIE) regeneration method is proposed: adopting photothermal materials to locate heat at the regeneration interface can prevent heat loss into the bulk solution and enhance efficiency. The thermal efficiency of the new regeneration method is about 2.5 times that of the conventional regeneration method. The type of desiccant greatly influences the performance of SDIE, but its impact has not been fully studied yet. To select the best desiccant for optimization, different solutions have been investigated with theoretical analysis and experiments. Considering both regeneration performance and economic benefits, the influence of some key parameters has been revealed. The results show that LiBr has the best regeneration performance, but MgCl2 and CaCl2 are more economical. Mixed desiccant could be a better substitute, showing a good balance between performance and cost. It was found that mixing CaCl2 and MgCl2 solutions in an appropriate proportion is a very cost-effective selection. These advances could make LDCS based on SDIE a potential competitor for the future air-conditioning system.

Residual periodontal ligament in the extraction socket promotes the dentin regeneration potential of DPSCs in the rabbit jaw

BackgroundBecause of the low regeneration efficiency and unclear underlying molecular mechanism, tooth regeneration applications are limited. In this study, we explored the influence of residual periodontal ligament on the dentin regeneration potential of dental pulp stem cells (DPSCs) in the jaw.MethodsTo establish a tooth regeneration model, the incisors of New Zealand white rabbits were extracted while preserving residual periodontal ligament, followed by the implantation of DPSCs. After 3 months, micro-computed tomography (micro-CT), stereomicroscopy and scanning electron microscopy (SEM) were used to observe the volume, morphology and microstructure of regenerated tissue. Histological staining and immunostaining analyses were used to observe the morphological characteristics and expression of the dentin-specific proteins DMP1 and DSPP. To explore the mechanism, DPSCs and periodontal ligament stem cells (PDLSCs) were cocultured in vitro, and RNA was collected from the DPSCs for RNA-seq and bioinformatic analysis.ResultsThe results of micro-CT and stereomicroscopy showed that the number of sites with regeneration and the volume of regenerated tissue in the DPSCs/PDL group (6/8, 1.07 ± 0.93 cm3) were larger than those in the DPSCs group (3/8, 0.23 ± 0.41 cm3). The results of SEM showed that the regenerated dentin-like tissue in the DPSCs and DPSCs/PDL groups contained dentin tubules. Haematoxylin and eosin staining and immunohistochemical staining indicated that compared with the DPSCs group, the DPSCs/PDL group showed more regular regenerated tissue and higher expression levels of the dentin-specific proteins DMP1 and DSPP (DMP1: P = 0.02, DSPP: P = 0.01). RNA-seq showed that the coculture of DPSCs with PDLSCs resulted in the DPSCs differentially expressing 427 mRNAs (285 upregulated and 142 downregulated), 41 lncRNAs (26 upregulated and 15 downregulated), 411 circRNAs (224 upregulated and 187 downregulated), and 19 miRNAs (13 upregulated and 5 downregulated). Bioinformatic analysis revealed related Gene Ontology function and signalling pathways, including extracellular matrix (ECM), tumour necrosis factor (TNF) signalling and chemokine signalling pathways.ConclusionsResidual periodontal ligament in the extraction socket promotes the dentin regeneration potential of DPSCs in the jaw. RNA-seq and bioinformatic analysis revealed that ECM, TNF signalling and chemokine signalling pathways may represent the key factors and signalling pathways.

Desalination of brackish groundwater using self-regeneration hybrid ion exchange and reverse osmosis system (HSIX-RO)

The United Nations International Decade for Action on Water for Sustainable Development (2018–2028) recognized the importance of water to sustainable development and the eradication of poverty and hunger. It voiced alarm over the worsening of issues such as access to clean water, water scarcity, and wastewater as a result of increasing populations and altered climates. One of the most promising solutions to the water shortage is desalination, which can increase the available water supply beyond the currently possible limit. In this study, we analyze the performance of a unique hybrid self-regeneration ion exchange and reverse osmosis (HSIX-RO) system for the desalination of brackish groundwater. In the pretreatment step for protecting RO membrane fouling, the traditional homogenized strong acid cation exchanger (Purolite C100) and shallow shell structured strong acid cation exchanger (Purolite SSTC65) were compared for their efficiency in removing hardness cations from brackish groundwater. The fixed-bed column study concluded that C100 and SSTC65 can treat brackish water containing 250 mg L−1 Ca2+ and 10,000 mg L−1 NaCl at approximately 80 and 76 bed volumes (BVs), respectively. Studying the efficiency of RO system, it has % RO recovery of >70 % at an optimized pressure of 120 psi. An upscale self-regeneration ion exchange and RO system, i.e., HSIX-RO, that can be applied for a pilot-scale study was proposed. This proposed study suggested that HSIX-RO can be suited for the desalination of brackish groundwater with minimum use of an additional salt and can be self-sustained using an automated control. It was noted that the HSIX-RO system cannot be effectively applied to groundwater (TDS < 5000 mg L−1) nor seawater (TDS > 30,000 mg L−1) contained high Ca2+ and Mg2+ due to low regeneration efficiency and short length service runs, respectively.

Anhydrous multi-hybrid absorbent with low viscosity and high regeneration efficiency for post-combustion CO2 capture

To reduce CO2 emissions, a new anhydrous multi-hybrid absorbent is developed for post-combustion CO2 capture. It was synthesized using tetraethylenepentamine-modified porous silica nanoparticles (TEPA-PSNs) as host unit and 2-[2-(dimethylamino)ethoxy]ethanol (DMEE) as solvent. The density and viscosity were higher with more TEPA-PSNs and lower temperatures. The viscosity of 50%-TEPA-PSNs/DMEE increased from 9.76 mPa s to 267.98 mPa s as TEPA-PSNs concentration rose from 5% to 20% at 27 °C. The effects of host unit concentration, amine group loading content, CO2 concentration in the gas phase, and temperature on CO2 absorption performance were investigated. The optimum absorption capacity was obtained with suitable TEPA-PSNs concentration and TEPA loading content to avoid the harmful effects of pore structure blockage and high viscosity on mass transfer. For 50%-TEPA-PSNs-10%/DMEE, higher CO2 concentration allowed better absorption capacity, which was 0.419 mmol/g at 20% CO2. The influence of increasing temperature on absorption capacity was first promoted and then inhibited, which was 0.410 mmol/g at 57 °C. Under 80 °C and N2 atmosphere regeneration conditions, the absorption capacity reached 95.0% of the initial use after five cycles. The absence of water in TEPA-PSNs/DMEE diminishes energy consumption and degradation. It is a promising CO2 capture material with low viscosity for post-combustion CO2 capture.

Improving the absorption load, high viscosity, and regeneration efficiency of CO2 capture using a novel tri-solvent biphasic solvents of TETA-AMP-1DMA2P.

Currently, biphasic solvents are receiving more attention for CO2 capture due to their energy-saving potential. Whereas, most of the current biphasic solvents still suffer from high viscosity and low regeneration efficiency. To solve this problem, a novel tri-solvent biphasic solvent triethylenetetramine (TETA)-2-amino-2-methyl-1-propanol (AMP)-1-dimethylamino-2-propanol (1DMA2P) was proposed in this study, and its absorption properties, viscosity changes, desorption properties, recyclability capacity, and reaction mechanism were explored. The results showed that the CO2 absorption load showed a trend of firstly increasing and then decreasing with the increase of AMP concentration. Although the volume of the rich phase increased with increasing AMP concentration after the absorption, it also decreases the viscosity growth. The viscosity of the solution decreased from 498mPa•s to 91mPa•s. During the desorption process, the maximal desorption rates of AMP-containing solvents is significantly greater than that of 2mol/L (M) TETA + 2M 1DMA2P (2T2D). Simultaneously, the recyclability capacity of the AMP-containing solvents were also significantly higher than that of 2T2D. The regeneration efficiency of 1.5M TETA + 0.5M AMP + 2M 1DMA2P (1.5T0.5A2D) was 81.92%. It was concluded by 13C NMR analysis that amino groups in TETA and AMP can react with CO2 to form carbamates and carbonates. Since AMP in the biphasic solution can generate free protons through various pathways during the desorption process, it promotes the decomposition of TETA-carbamate. This process achieves the deep stripping of CO2 in biphasic solvent. Overall, TETA-AMP-1DMA2P solution is a promising energy-saving candidate for industrial CO2 capture due to its competitive absorption-desorption performance and low viscosity.

Bioinspired Metalation of the Metal‐Organic Framework MIL‐125‐NH2 for Photocatalytic NADH Regeneration and Gas‐Liquid‐Solid Three‐Phase Enzymatic CO2 Reduction

AbstractCoenzyme NADH regeneration is crucial for sustained photoenzymatic catalysis of CO2 reduction. However, light‐driven NADH regeneration still suffers from the low regeneration efficiency and requires the use of a homogeneous Rh complex. Herein, a Rh complex‐based electron transfer unit was chemically attached onto the linker of the MIL‐125‐NH2. The coupling between the light‐harvesting iminopyridine unit and electron‐transferring Rh‐complex facilitated the photo‐induced electron transfer for the NADH regeneration with the yield of 66.4 % in 60 mins for 5 cycles. The formate dehydrogenase was further deposited onto the hydrophobic layer of the membrane by a reverse filtering technique, which forms the gas‐liquid‐solid reaction interface around the enzyme site. It gave an enhanced formic acid yield of 9.5 mM in 24 hours coupled with the in situ regenerated NADH. The work could shed light on the construction of integrated inorganic‐enzyme hybrid systems for artificial photosynthesis.

Overexpression of TcCHS Increases Pyrethrin Content When Using a Genotype-Independent Transformation System in Pyrethrum (Tanacetum cinerariifolium).

Pyrethrum (Tanacetum cinerariifolium) is one of the most important industrial crops for the extraction of pyrethrins, which are natural insecticidal compounds. Progress in pyrethrum molecular breeding with the objective of increasing pyrethrin content has been slow for lack of a suitable gene transfer system. Regeneration recalcitrance is a crucial barrier to establishing a genetic transformation system in pyrethrum. Therefore, in this study, an Agrobacterium-mediated transformation system in pyrethrum was developed using shoot apical meristems from germinated seedlings. Factors affecting transformation efficiency were optimized. Optimal conditions included explants at the “no true leaf” stage with a half apical meristem, an Agrobacterium tumefaciens cell density of OD600 = 0.5, two days of cocultivation, and the incorporation of 1.5 mg L−1 6-BA and 30 mg L−1 kanamycin into the selection medium. Under the optimized conditions, two expression cassettes (proTcCHS-GUS and proRbcS-TcCHS) were successfully transformed into pyrethrum. Polymerase chain reaction (PCR), Southern blotting, reverse-transcription quantitative PCR (RT-qPCR), and histochemical staining confirmed the identity of proTcCHS-GUS transgenic plants. PCR and RT-qPCR analyses confirmed the identity of proRbcS-TcCHS transgenic plants. The transformation efficiency was 0.83% (5 transgenic lines/600 infected explants). The relative concentration of pyrethrins in proRbcS-TcCHS transformants (OX T0-1: 1.50% or OX T0-2: 1.24%) was higher than that in nontransformed plants (WT: 0.76%). Thus, the genetic transformation system overcame the low regeneration efficiency and integrated a foreign gene into the pyrethrum genome. The new system is a suitable and effective tool for creating high-yielding cultivars of pyrethrum.

Bioinspired Metalation of the Metal-Organic Framework MIL-125-NH2 for Photocatalytic NADH Regeneration and Gas-Liquid-Solid Three-Phase Enzymatic CO2 Reduction.

Coenzyme NADH regeneration is crucial for sustained photoenzymatic catalysis of CO2 reduction. However, light-driven NADH regeneration still suffers from the low regeneration efficiency and requires the use of a homogeneous Rh complex. Herein, a Rh complex-based electron transfer unit was chemically attached onto the linker of the MIL-125-NH2 . The coupling between the light-harvesting iminopyridine unit and electron-transferring Rh-complex facilitated the photo-induced electron transfer for the NADH regeneration with the yield of 66.4 % in 60 mins for 5 cycles. The formate dehydrogenase was further deposited onto the hydrophobic layer of the membrane by a reverse filtering technique, which forms the gas-liquid-solid reaction interface around the enzyme site. It gave an enhanced formic acid yield of 9.5 mM in 24 hours coupled with the in situ regenerated NADH. The work could shed light on the construction of integrated inorganic-enzyme hybrid systems for artificial photosynthesis.

Callogenesis and Plant Regeneration in Peony (Paeonia × suffruticosa) Using Flower Petal Explants

Peony is a traditional Chinese flower with significant ornamental and medicinal value. However, there are still problems, such as serious browning, difficulties in differentiation, and rooting and low regeneration efficiency in the process of the regeneration system established, which have hindered the development of transgenic peony technology. Establishing an efficient regeneration system is considered to be an important goal among peony researchers. Here, we describe a protocol for high-frequency callus induction and establishment of peony plants using flower petals as explants. Murashige and Skoog (MS) medium supplemented with 2.0 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D), 1.5 mg/L N-(phenylmethyl)-9H-purin-6-amine (6-BA), and 0.3 mg/L 1-naphthylacetic acid (NAA) was identified as the best medium for callus induction, achieving an induction rate of up to 98.52%. The highest peony proliferation rate (234%) was achieved on MS supplemented with 0.2 mg/L NAA and 3.0 mg/L 6-BA. The highest callus differentiation rate (34.81%) was achieved on MS supplemented with 2.0 mg/L 6-BA and 0.5 mg/L zeatin (ZT). The highest rooting rate was 23.33% when using 1/2 MS supplemented with 0.1 mg/L NAA and 0.05 mg/L 3-indolebutyric acid (IBA). After acclimation, the plants were transferred to pots, where they showed robust growth. We also observed the surface structures of the calluses using scanning electron microscopy and found that the differentiation characteristics of the calluses were hugely variable and that different surface structures appeared to affect bud differentiation efficiency. The efficient and rapid system for regenerating peonies using petal cultures established here will create new opportunities for the mass reproduction and genetic engineering of peony plants.

Development and optimization of a Barley stripe mosaic virus-mediated gene editing system to improve Fusarium head blight resistance in wheat.

Development and optimization of a Barley stripe mosaic virus-mediated gene editing system to improve Fusarium head blight resistance in wheat.

Improvement of plant regeneration efficiency using polyamines for double haploid production in wheat (Triticum aestivum)

Polyamines are low molecular weight nitrogen containing compounds present in all living organisms. These are considered to be a new class of plant hormones, and play a positive role in plant growth and developmental processes including cell division, in vitro organogenesis and somatic, and zygotic embryogenesis. In our study, three polyamines PUT, SPD and SPM were used alone and in combinations in plant regeneration medium for in vitro plant regeneration from embryo developed through wheat × maize cross for double haploid production in wheat. Usually, these embryos have low regeneration efficiency but polyamines addition alone and in combinations in plant regeneration medium enhanced plant regeneration frequency as compared to control. Lower concentration of polyamines (1 and 2 ppm) has been found to be effective as compared to higher concentration (5 ppm). The polyamine concentration 1 ppm found to be promising concentration to improve plant regeneration. The combination of polyamines PUT+SPD (0.5 ppm+0.5ppm) proved better than other combinations to enhance plant regeneration frequency. The combination of PUT+SPD+SPM (0.5 ppm + 0.25 ppm + 0.25 ppm) although reduced plant regeneration frequency but plants were more vigorous and healthy.

Enhancement of the electro-Fenton degradation of organic contaminant by accelerating Fe3+/Fe2+ cycle using hydroxylamine

The Electro-Fenton process can generate reactive oxygen species capable of oxidizing refractory organic contaminants. However, low regeneration efficiency of Fe2+ restricts its application. Herein, hydroxylamine (HA) was added into the Electro-Fenton (HA/Electro-Fenton) process to accelerate the transformation of Fe3+ to Fe2+. Using dimethyl phthalate (DMP) as target contaminant, the HA/Electro-Fenton system alleviated the two-stage reaction process and accelerated the removal of DMP in the pH range of 2.0–6.0. With improving DMP concentration from 5 mg L-1 to 50 mg L-1, their degradation rate increased in the HA/Electro-Fenton system, while decreased in the Electro-Fenton system. The addition of HA had negligible effect on electro-generation of H2O2, but facilitate the redox cycle of Fe3+/Fe2+ and the generation of hydroxyl radicals, thus improving the degradation of DMP. The final transformation products of HA were N2, N2O, and NO3−. The presence of PO43− improved DMP degradation, while Cl− and organic matters inhibited DMP removal in varying degrees. This study provided useful reference to solve the low efficiency of Fe3+/Fe2+ cycle and expand the pH application range in the Electro-Fenton process.

An innovative compound bed of EDI device with enhancing ion-exchange resins regeneration efficiency.

Electrodeionization (EDI) technology is limited by low regeneration efficiency of ion exchange resins, requirements of high-quality influent water, fouling of the ion exchange membrane and electrode, etc. In this work, a novel bed type called a compound bed in which cation and anion exchange resins were near the cation and anion exchange membrane and placed in layers, was proposed to implement high-efficiency regeneration of ion exchange resins. The influence of different operating conditions on the regeneration efficiency of ion exchange resins was elucidated as well. The regeneration efficiency of ion exchange resins could reach 73.1%, when the device was operated for 5 h under current density of 9 mA/cm2, with a cation and anion exchange resins ratio of 2: 3, influent water conductivity of 1,360 μS/cm and hardness of 400 mg/L. Therefore, the proposed compound bed structure not only widened the inlet water conditions, but also achieved the high-efficiency regeneration of ion exchange resins and anti-fouling of membranes and electrodes.