Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 52

年份

2023 2

2022 5

2021 2

2020 2

2019 8

2018 1

2017 1

2016 6

2015 1

2014 1

2013 3

2012 4

2011 3

2010 5

2009 2

2008 2

2007 1

展开︾

关键词

再生 3

干细胞 2

3D打印 1

仿生 1

仿生牙釉质 1

修复 1

免疫微环境调控 1

内球配位 1

再矿化 1

制浆 1

吸附 1

器官形成 1

基因技术 1

心肌梗死 1

心脏再生 1

抗体产生 1

损伤 1

机理 1

植株再生 1

展开︾

检索范围：

排序：展示方式：

Dental stem cell and dental tissue regeneration

Qiming Zhai, Zhiwei Dong, Wei Wang, Bei Li, Yan Jin

《医学前沿（英文）》 2019年第13卷第2期页码 152-159 doi: 10.1007/s11684-018-0628-x

摘要： The teeth are highly differentiated chewing organs formed by the development of tooth germ tissue located in the jaw and consist of the enamel, dentin, cementum, pulp, and periodontal tissue. Moreover, the teeth have a complicated regulatory mechanism, special histologic origin, diverse structure, and important function in mastication, articulation, and aesthetics. These characteristics, to a certain extent, greatly complicate the research in tooth regeneration. Recently, new ideas for tooth and tissue regeneration have begun to appear with rapid developments in the theories and technologies in tissue engineering. Numerous types of stem cells have been isolated from dental tissue, such as dental pulp stem cells (DPSCs), stem cells isolated from human pulp of exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), stem cells from apical papilla (SCAPs), and dental follicle cells (DFCs). All these cells can regenerate the tissue of tooth. This review outlines the cell types and strategies of stem cell therapy applied in tooth regeneration, in order to provide theoretical basis for clinical treatments.

关键词： stem cells pulp regeneration periodontal regeneration

HTML PDF 收藏

Self-etching adhesives: possible new pulp capping agents to vital pulp therapy

null

《医学前沿（英文）》 2011年第5卷第1期页码 77-79 doi: 10.1007/s11684-010-0104-8

摘要：

Pulp capping is one of the solving for keeping vital pulp in the case of dentin caries, reversible pulpitis or traumatic pulp exposure. The presence of bacteria on the cavity walls or in the pulp was the major factor that leads to the failure of pulp capping. Traditional pulp capping agent, calcium hydroxide, may not prevent microleakage. Self-etching system is a newly developed adhesive system, which could provide less microleakage and would not break down or dissolve, preventing the oral fluids and bacteria from the pulp along the cavity wall. This may reduce such clinical problems as postoperative sensitivity, secondary caries and marginal discoloration. Researches showed that some kinds of self-etching adhesives induced the mild to moderate inflammatory pulp response, with negative bacterial staining. Inclusion of antibacterial components into self-etching system, such as 12- methacryloyloxydodecylpyridinium bromide (MDPB) may inhibit bacteria and provide better clinical effects. It is speculated that using the self-etching adhesive system containing the antibacterial agent, such as MDPB, to the dental pulp directly or indirectly, may inhibit bacteria after the placement of restoration as well as residual bacteria in the cavity.

关键词： dental pulp pulp capping self-etching adhesives antibacterial components

HTML PDF 收藏

Production of pectic extracts from sugar beet pulp with antiproliferative activity on a breast cancer

Jacqueline CONCHA, Caroline WEINSTEIN, María Elvira Zú?IGA

《化学科学与工程前沿（英文）》 2013年第7卷第4期页码 482-489 doi: 10.1007/s11705-013-1342-5

摘要： In the last years, sugar beet pectins have been the subject of several investigations involving extraction methodologies, chemical composition and functional properties. The structure of pectins, which depends on the extraction method, is decisive in their capacity to induce apoptosis on several cancer cell lines like colon, prostate and breast. In this work, sugar beet pectin extraction was performed in the following steps: lipid extraction with hexane, removal of soluble complex carbohydrates and proteins, and enzymatic treatment with amyloglucosidase, protease, and pectinase. The enzymatic treatment was carried out with Rohapect DA6L under the following conditions: 50°C, pH 4.0, 2% enzyme/substrate (E/S) ratio, 15 h, and a solid to liquid ratio of 1 ∶ 10. The pectic extract showed a degree of polymerization (DP) profile of 55.8% with DP≥7; 4.9% with DP6; 5.8% between DP2 and DP6 ; 4.7% with DP2; and 28.8% with DP1. The pectic extract was examined for its antiproliferative activity on the MCF-7 breast cancer cell line. At a concentration range of 12.5–25 mg/mL the pectic extract killed 80.6% of the cells, exhibiting a higher antiproliferative activity than 4-hydroxytamoxifen (4-OHT), a classical anticancer drug, which killed 56.5% of the cells.

关键词： pectic extracts antiproliferative activity breast cancer enzymatic treatment

HTML PDF 收藏

Migration of manganese and iron during the adsorption-regeneration cycles for arsenic removal

Fangfang CHANG, Jiuhui QU, Xu ZHAO, Wenjun LIU, Kun WU

《环境科学与工程前沿（英文）》 2011年第5卷第4期页码 512-518 doi: 10.1007/s11783-011-0372-9

摘要： Fe-Mn binary oxide incorporated into porous diatomite (FMBO-diatomite) was prepared in situ and regenerated in a fixed-bed column for arsenite [As(III)] and arsenate [As(V)] removal. Four consecutive adsorption cycles were operated under the following conditions: Initial arsenic concentration of 0.1 mg·L , empty bed contact time of 5 min, and pH 7.0. About 3000, 3300, 3800, and 4500 bed volumes of eligible effluent (arsenic concentration≤0.01 mg·L ) were obtained in four As(III) adsorption cycles; while about 2000, 2300, 2500, and 3100 bed volumes of eligible effluent were obtained in four As(V) adsorption cycles. The dissection results of FMBO-diatomite fixed-bed exhibited that small amounts of manganese and iron were transferred from the top of the fixed-bed to the bottom of the fixed-bed during As(III) removal process. Compared to the extremely low concentration of iron (<0.01 mg·L ), the fluctuation concentration of Mn in effluent of the As(III) removal column was in a range of 0.01–0.08 mg·L . The release of manganese suggested that manganese oxides played an important role in As(III) oxidation. Determined with the US EPA toxicity characteristic leaching procedure (TCLP), the leaching risk of As(III) on exhausted FMBO-diatomite was lower than that of As(V).

关键词： arsenic adsorption filtration regeneration fixed-bed

HTML PDF 收藏

biomaterial transplantation and genetic enhancement of intrinsic growth capacities to promote CNS axon regeneration

Bin Yu, Xiaosong Gu

《医学前沿（英文）》 2019年第13卷第2期页码 131-137 doi: 10.1007/s11684-018-0642-z

摘要： The inhibitory environment that surrounds the lesion site and the lack of intrinsic regenerative capacity of the adult mammalian central nervous system (CNS) impede the regrowth of injured axons and thereby the reestablishment of neural circuits required for functional recovery after spinal cord injuries (SCI). To circumvent these barriers, biomaterial scaffolds are applied to bridge the lesion gaps for the regrowing axons to follow, and, often by combining stem cell transplantation, to enable the local environment in the growth-supportive direction. Manipulations, such as the modulation of PTEN/mTOR pathways, can also enhance intrinsic CNS axon regrowth after injury. Given the complex pathophysiology of SCI, combining biomaterial scaffolds and genetic manipulation may provide synergistic effects and promote maximal axonal regrowth. Future directions will primarily focus on the translatability of these approaches and promote therapeutic avenues toward the functional rehabilitation of patients with SCIs.

关键词： spinal cord injury biomaterial extrinsic barrier intrinsic regeneration capacity

HTML PDF 收藏

Synthesis of hydroxymethylfurfural and furfural from hardwood and softwood pulp using ferric sulphate

Agneev Mukherjee, Guillermo Portillo-Perez, Marie-Josée Dumont

《化学科学与工程前沿（英文）》 2019年第13卷第3期页码 531-542 doi: 10.1007/s11705-019-1814-3

摘要： Hydroxymethylfurfural (HMF) and furfural are promising chemicals for the creation of a bio-based economy. The development of an inexpensive catalytic system for converting cellulosic biomass into these chemicals is an important step in this regard. Ferric sulphate is a common, cheap and non-toxic Lewis acid that has been used to catalyse reactions such as wood depolymerisation. In this work, ferric sulphate was used to help the production of HMF and furfural from hardwood and softwood pulps. It was found that for hardwood pulp, the use of ferric sulphate alone gave a maximum HMF yield of 31.6 mol-%. The addition of the ionic liquid [BMIM]Cl or HCl as co-catalysts did not lead to an increase in the yields obtained. A prior decationisation step, however, resulted in HMF yields of 50.4 mol-%. Softwood pulp was harder to depolymerise than hardwood, with a yield of 28.7% obtained using ferric sulphate alone. The maximum HMF yield from softwood, 37.9 mol-%, was obtained using a combination of ferric sulphate and dilute HCl. It was thus concluded that ferric sulphate is a promising catalyst for HMF synthesis from cellulosic biomass.

关键词： 5-hydroxymethylfurfural hardwood softwood ferric sulphate biorefinery

HTML PDF 收藏

Bone regeneration by stem cell and tissue engineering in oral and maxillofacial region

Zhiyuan Zhang

《医学前沿（英文）》 2011年第5卷第4期页码 401-413 doi: 10.1007/s11684-011-0161-7

摘要： Clinical imperatives for the reconstruction of jaw bone defects or resorbed alveolar ridge require new therapies or procedures instead of autologous/allogeneic bone grafts. Regenerative medicine, based on stem cell science and tissue engineering technology, is considered as an ideal alternative strategy for bone regeneration. In this paper, we review the current choices of cell source and strategies on directing the osteogenic differentiation of stem cells. The preclinical animal models for bone regeneration and the key translational points to clinical success in oral and maxillofacial region are also discussed. We propose comprehensive strategies based on stem cell and tissue engineering researches, allowing for clinical application in oral and maxillofacial region.

关键词： bone regeneration animal models translational strategies oral and maxillofacial region

HTML PDF 收藏

Investigation on regeneration and energy storage characteristics of a solar liquid desiccant air-conditioning

SHI Mingheng, DU Bin, ZHAO Yun

《能源前沿（英文）》 2007年第1卷第1期页码 85-90 doi: 10.1007/s11708-007-0008-8

摘要： Solar liquid desiccant air-conditioner is a new air-conditioning system in which liquid desiccant can be regenerated by solar energy and energy can be stored in the form of chemical energy in the liquid desiccant. In this paper regeneration and energy storage characteristics were studied theoretically and experimentally. Two criterion equations for heat and mass transfer in the regeneration process were obtained. The main factors that influence the regeneration process were analyzed. A principal solar liquid desiccant air-conditioning system under energy storage operating mode is proposed.

关键词： desiccant air-conditioning regeneration process air-conditioning system energy regeneration

HTML PDF 收藏

Evaluation of power regeneration in primary suspension for a railway vehicle

Ruichen WANG, Zhiwei WANG

《机械工程前沿（英文）》 2020年第15卷第2期页码 265-278 doi: 10.1007/s11465-019-0571-9

摘要： To improve the fuel economy of rail vehicles, this study presents the feasibility of using power regenerating dampers (PRDs) in the primary suspension systems of railway vehicles and evaluates the potential and recoverable power that can be obtained. PRDs are configured as hydraulic electromagnetic-based railway primary vertical dampers and evaluated in parallel and series modes (with and without a viscous damper). Hydraulic configuration converts the linear behavior of the track into a unidirectional rotation of the generator, and the electromagnetic configuration provides a controllable damping force to the primary suspension system. In several case studies, generic railway vehicle primary suspension systems that are configured to include a PRD in the two configuration modes are modeled using computer simulations. The simulations are performed on measured tracks with typical irregularities for a generic UK passenger route. The performance of the modified vehicle is evaluated with respect to key performance indicators, including regenerated power, ride comfort, and running safety. Results indicate that PRDs can simultaneously replace conventional primary vertical dampers, regenerate power, and exhibit desirable dynamic performance. A peak power efficiency of 79.87% is theoretically obtained in series mode on a top-quality German Intercity Express track (Track 270) at a vehicle speed of 160 mile/h (~257 km/h).

关键词： railway vehicle primary damper power regeneration ride comfort running safety

HTML PDF 收藏

Role of Wnt and Notch signaling in regulating hair cell regeneration in the cochlea

null

《医学前沿（英文）》 2016年第10卷第3期页码 237-249 doi: 10.1007/s11684-016-0464-9

摘要：

Sensory hair cells in the inner ear are responsible for sound recognition. Damage to hair cells in adult mammals causes permanent hearing impairment because these cells cannot regenerate. By contrast, newborn mammals possess limited regenerative capacity because of the active participation of various signaling pathways, including Wnt and Notch signaling. The Wnt and Notch pathways are highly sophisticated and conserved signaling pathways that control multiple cellular events necessary for the formation of sensory hair cells. Both signaling pathways allow resident supporting cells to regenerate hair cells in the neonatal cochlea. In this regard, Wnt and Notch signaling has gained increased research attention in hair cell regeneration. This review presents the current understanding of the Wnt and Notch signaling pathways in the auditory portion of the inner ear and discusses the possibilities of controlling these pathways with the hair cell fate determiner Atoh1 to regulate hair cell regeneration in the mammalian cochlea.

关键词： inner ear cochlea hair cell regeneration Wnt Notch signaling pathways

HTML PDF 收藏

Preparation and characteristics of TEMPO-oxidized cellulose nanofibrils from bamboo pulp and their oxygen-barrier

Bozhen Wu, Biyao Geng, Yufei Chen, Hongzhi Liu, Guangyao Li, Qiang Wu

《化学科学与工程前沿（英文）》 2017年第11卷第4期页码 554-563 doi: 10.1007/s11705-017-1673-8

摘要： Bleached bamboo kraft pulp was pretreated by 2,2,6,6-tetramethylpiperidine-1-oxy radical (TEMPO)-mediated oxidation using a TEMPO/NaBr/NaClO system at pH= 10 in water to facilitate mechanical disintegration into TEMPO-oxidized cellulose nanofibrils (TO-CNs). A series of TO-CNs with different carboxylate contents were obtained by varying amounts of added NaClO. An increase in carboxylate contents results in aqueous TO-CN dispersions with higher yield, zeta potential values, and optical transparency. When carboxylate groups are introduced, the DP value of the TO-CNs remarkably decreases and then levels off. And the presence of hemicellulose in the pulp is favorable to TEMPO oxidization. After the oxidization, the native cellulose I crystalline structure and crystal size of bamboo pulp are almost maintained. TEM micrographs revealed that the degree of nanofibrillation is directly proportional to the carboxylate contents. With increasing carboxylate contents, the free-standing TO-CN films becomes more transparent and mechanically stronger. The oxygen permeability of PLA films drastically decreases from 355 for neat PLA to 8.4 mL·m ·d after coating a thin layer of TO-CN with a carboxylate content of 1.8 mmol·g . Therefore, inexpensive and abundant bamboo pulp would be a promising starting material to isolate cellulose nanfibrils for oxygen-barrier applications.

关键词： bamboo TEMPO cellulose nanofibrils oxygen barrier

HTML PDF 收藏

Electro-assisted regeneration of ion exchange resins

LIU Zhigang, WANG Ying, LI Yansheng, CHANG Hui

《环境科学与工程前沿（英文）》 2008年第2卷第4期页码 410-414 doi: 10.1007/s11783-008-0069-x

摘要： Electro-assisted regeneration (EAR) for the mixed bed of strongly acidic cation and weakly basic anion exchange resins with the Al(OH) suspension in a three-compartment cell was investigated. The desalination experiments were carried out to evaluate the characteristic of the regenerated mixed resins. Experimental results showed that the efficiency of resin regeneration was strictly dependent on the voltage, regeneration time, and feed regenerant flow rate. The amount of the effluent reached 50 times the volume of the resins bed, and the conductivity was less than 1.0 ?s/cm. Compared to the conventional ER, the total effluent volume of EAR was about 1000 mL more than that of ER under the same conditions, and the outlet conductivity was significantly lower. The desalination and regeneration reaction mechanisms of the mixed resins indicated the regeneration efficiency of resin with Al(OH) as the regenerant was much higher than that with HO.

关键词： effluent volume acidic three-compartment weakly exchange

HTML PDF 收藏

Sulfidation/regeneration multicycle testing of nickel-modified ZnFe

Wei LI, Jinju GUO, Jiejie HUANG, Jiaotao ZHAO

《化学科学与工程前沿（英文）》 2010年第4卷第4期页码 435-440 doi: 10.1007/s11705-010-0506-9

摘要： A commercial metal oxide sorbent for the desulphurization of coal-derived gas requires high desulphurization reactivity, mechanical strength, ability to regenerate, and stability to endure many sulfidation-regeneration cycles. In this paper, the sulfur capacity and multiple cycles of a nickel-modified ZnFe O sorbent prepared by the sol-gel auto-combustion method were measured in a fixed-bed reactor at middle temperature of 300°C (sulfidation temperature) and 500°C (regeneration temperature). Also, the BET surface area, pore volume, average pore diameter and X-ray diffraction (XRD) patterns of the sorbent through multicycles were studied. Multicycle runs indicate that the sulfidation reactivity decreases slightly during the second cycle and keeps steady in the following cycles. The results indicate that the nickel-modified ZnFe O keeps high reactivity and structural stability in the multicycle testing of sulfidation/regeneration.

关键词： hot gas desulphurization nickel-modified ZnFe₂O₄ sulfidation/regeneration

HTML PDF 收藏

Current advances for bone regeneration based on tissue engineering strategies

Rui Shi, Yuelong Huang, Chi Ma, Chengai Wu, Wei Tian

《医学前沿（英文）》 2019年第13卷第2期页码 160-188 doi: 10.1007/s11684-018-0629-9

摘要： Bone tissue engineering (BTE) is a rapidly developing strategy for repairing critical-sized bone defects to address the unmet need for bone augmentation and skeletal repair. Effective therapies for bone regeneration primarily require the coordinated combination of innovative scaffolds, seed cells, and biological factors. However, current techniques in bone tissue engineering have not yet reached valid translation into clinical applications because of several limitations, such as weaker osteogenic differentiation, inadequate vascularization of scaffolds, and inefficient growth factor delivery. Therefore, further standardized protocols and innovative measures are required to overcome these shortcomings and facilitate the clinical application of these techniques to enhance bone regeneration. Given the deficiency of comprehensive studies in the development in BTE, our review systematically introduces the new types of biomimetic and bifunctional scaffolds. We describe the cell sources, biology of seed cells, growth factors, vascular development, and the interactions of relevant molecules. Furthermore, we discuss the challenges and perspectives that may propel the direction of future clinical delivery in bone regeneration.

关键词： bone tissue engineering stem cell bone scaffold growth factor bone regeneration