Search

Hui Wang,1,* Xiaonan Zhou,2,* Xingyu Li,1,* Zeng Xu,1,* Qingbing Meng,3 Jianxi Wang,1 Xiaolong Shen,1 Huajiang Chen,1 Wen Yuan,1 Xiaodong Wu1 1Department of Orthopedics, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, People’s Republic of China; 2Department of Anesthesiology, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, People’s Republic of China; 3Department of Orthopedics, Shanghai Zhongshan Hospital, Fudan University Shanghai School of Medicine, Shanghai, People’s Republic of China*These authors contributed equally to this workCorrespondence: Huajiang Chen; Xiaodong Wu, Email chenhuajspine@163.com; wuxiaodongspine@163.comIntroduction: Low back pain following transforaminal endoscopic lumbar discectomy (TELD) is prevalent (15– 25% incidence). Modifying TELD techniques to avoid excessive disc removal has been suggested to reduce such pain. Facet injury, re-herniation, and disc space collapse might contribute. This retrospective study aimed to explore factors linked to post-TELD low back pain.Methods: A total of 351 patients with L3/4, L4/5, and L5/S1 intervertebral lumbar disc herniations, who underwent TELD at two spine centers, were included. Patients were followed for one year. Low back and leg pain visual analogue scale (VAS) scores, Oswestry Disability Index (ODI), Pfirrmann grade, and disc height were measured at 3 months and 1 year. Correlation analyses examined links between postoperative low back pain VAS scores, age, sex, disc/vertebrae height ratio (D/V H ratio), Pfirrmann grade, cannula position grade, re-herniation grade, high-intensity zone (HIZ), disc calcification, surgical grade, and other factors. Significant variables were identified using partial least square tests, with variable importance in projection (VIP) values quantifying their impact on low back pain.Results: Univariate analysis indicated that surgical grade correlated with long-term postoperative low

Actualizing full singlet exciton yield via a reverse intersystem crossing from the high-lying triplet state to singlet state, namely, “hot exciton” mechanism, holds great potential for high-performance fluorescent organic light-emitting diodes (OLEDs). However, incorporating comprehensive insights into the mechanism and effective molecular design strategies still remains challenging. Herein, three blue emitters (CNNPI, 2TriPE-CNNPI, and 2CzPh-CNNPI) with a distinct local excited (LE) state and charge-transfer (CT) state distributions in excited states are designed and synthesized. They show prominent hybridized local and charge-transfer (HLCT) states and aggregation-induced emission enhancement properties. The “hot exciton” mechanism based on these emitters reveals that a balanced LE/CT distribution can simultaneously boost photoluminescence efficiency and exciton utilization. In particular, a nearly 100% exciton utilization is achieved in the electroluminescence (EL) process of 2CzPh-CNNPI. Moreover, employing 2CzPh-CNNPI as the emitter, emissive dopant, and sensitizing host, respectively, the EL performances of the corresponding nondoped pure-blue, doped deep-blue, and HLCT-sensitized fluorescent OLEDs are among the most efficient OLEDs with a “hot exciton” mechanism to date. These results could shed light on the design principles for “hot exciton” materials and inspire the development of next-generation high-performance OLEDs. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

As the congener of organic light-emitting diodes, polymeric light-emitting diodes (PLEDs) possess a number of distinct merits, such as a low-cost wet fabrication process, which make them applicable in large-area flexible display and lighting fields. However, most emissive polymers used in PLEDs suffer from the aggregation-caused quenching (ACQ) effect, which makes the device show large efficiency roll-off. In this work, two polymers, pTPE-DPA-Cz and pTPE-DPA-Flu, featuring aggregation-induced emission (AIE) characteristics were facilely synthesized through Suzuki-Miyaura polycoupling reaction by incorporating the AIE unit of TPE-DPA in their main chains. The resultant polymers possess good film-forming ability, excellent thermal stability and high photoluminescence quantum yields (PLQYs) in their film states, facilitating the fabrication of PLEDs through a solution process. Indeed, the PLEDs using pTPE-DPA-Cz and pTPE-DPA-Flu as emitting layers (EMLs) could achieve a maximum external quantum efficiency (EQE) of 3.26% (doped EML) and current efficiency of 3.69 cd A(-1) (non-doped EML). Notably, all the devices exhibit a quite low efficiency roll-off. This work indicates that AIE polymers are ideal candidates for the construction of high performance PLEDs with low efficiency roll-off.

Planarized intramolecular charge transfer(PLICT) state can facilitate the fluorescence process thanks to the relative excellent planarity. Recently, we have discovered that the excited state quinone-conformation induced planarization(ESQIP) occurring on tetraphenylpyrazine(TPP) based derivatives could furnish them with PLICT feature. Unlike to the well-known intramolecular charge transfer, strengthening the electron-donating nature on the donor(D) moiety did not impair the PLICT. The calculation results showed that planarization of the TPP based compounds scarcely accompanied with energy wastage while amount of energy was required for the torsion on geometries. In the polar solvents, the energy consumption for planarization could further decrease, but that for twisting structure would increase. To take advantage of the transformation of the frontier orbitals’ distribution, the PLICT type materials would perform a potential application on organic light-emitting diodes(OLEDs). © 2019, Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH.

Actualizing full singlet exciton yield via a reverse intersystem crossing from the high-lying triplet state to singlet state, namely, “hot exciton” mechanism, holds great potential for high-performance fluorescent organic light-emitting diodes (OLEDs). However, incorporating comprehensive insights into the mechanism and effective molecular design strategies still remains challenging. Herein, three blue emitters (CNNPI, 2TriPE-CNNPI, and 2CzPh-CNNPI) with a distinct local excited (LE) state and charge-transfer (CT) state distributions in excited states are designed and synthesized. They show prominent hybridized local and charge-transfer (HLCT) states and aggregation-induced emission enhancement properties. The “hot exciton” mechanism based on these emitters reveals that a balanced LE/CT distribution can simultaneously boost photoluminescence efficiency and exciton utilization. In particular, a nearly 100% exciton utilization is achieved in the electroluminescence (EL) process of 2CzPh-CNNPI. Moreover, employing 2CzPh-CNNPI as the emitter, emissive dopant, and sensitizing host, respectively, the EL performances of the corresponding nondoped pure-blue, doped deep-blue, and HLCT-sensitized fluorescent OLEDs are among the most efficient OLEDs with a “hot exciton” mechanism to date. These results could shed light on the design principles for “hot exciton” materials and inspire the development of next-generation high-performance OLEDs. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

As the congener of organic light-emitting diodes, polymeric light-emitting diodes (PLEDs) possess a number of distinct merits, such as a low-cost wet fabrication process, which make them applicable in large-area flexible display and lighting fields. However, most emissive polymers used in PLEDs suffer from the aggregation-caused quenching (ACQ) effect, which makes the device show large efficiency roll-off. In this work, two polymers, pTPE-DPA-Cz and pTPE-DPA-Flu, featuring aggregation-induced emission (AIE) characteristics were facilely synthesized through Suzuki-Miyaura polycoupling reaction by incorporating the AIE unit of TPE-DPA in their main chains. The resultant polymers possess good film-forming ability, excellent thermal stability and high photoluminescence quantum yields (PLQYs) in their film states, facilitating the fabrication of PLEDs through a solution process. Indeed, the PLEDs using pTPE-DPA-Cz and pTPE-DPA-Flu as emitting layers (EMLs) could achieve a maximum external quantum efficiency (EQE) of 3.26% (doped EML) and current efficiency of 3.69 cd A(-1) (non-doped EML). Notably, all the devices exhibit a quite low efficiency roll-off. This work indicates that AIE polymers are ideal candidates for the construction of high performance PLEDs with low efficiency roll-off.

Planarized intramolecular charge transfer(PLICT) state can facilitate the fluorescence process thanks to the relative excellent planarity. Recently, we have discovered that the excited state quinone-conformation induced planarization(ESQIP) occurring on tetraphenylpyrazine(TPP) based derivatives could furnish them with PLICT feature. Unlike to the well-known intramolecular charge transfer, strengthening the electron-donating nature on the donor(D) moiety did not impair the PLICT. The calculation results showed that planarization of the TPP based compounds scarcely accompanied with energy wastage while amount of energy was required for the torsion on geometries. In the polar solvents, the energy consumption for planarization could further decrease, but that for twisting structure would increase. To take advantage of the transformation of the frontier orbitals’ distribution, the PLICT type materials would perform a potential application on organic light-emitting diodes(OLEDs). © 2019, Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH.

Actualizing full singlet exciton yield via a reverse intersystem crossing from the high-lying triplet state to singlet state, namely, “hot exciton” mechanism, holds great potential for high-performance fluorescent organic light-emitting diodes (OLEDs). However, incorporating comprehensive insights into the mechanism and effective molecular design strategies still remains challenging. Herein, three blue emitters (CNNPI, 2TriPE-CNNPI, and 2CzPh-CNNPI) with a distinct local excited (LE) state and charge-transfer (CT) state distributions in excited states are designed and synthesized. They show prominent hybridized local and charge-transfer (HLCT) states and aggregation-induced emission enhancement properties. The “hot exciton” mechanism based on these emitters reveals that a balanced LE/CT distribution can simultaneously boost photoluminescence efficiency and exciton utilization. In particular, a nearly 100% exciton utilization is achieved in the electroluminescence (EL) process of 2CzPh-CNNPI. Moreover, employing 2CzPh-CNNPI as the emitter, emissive dopant, and sensitizing host, respectively, the EL performances of the corresponding nondoped pure-blue, doped deep-blue, and HLCT-sensitized fluorescent OLEDs are among the most efficient OLEDs with a “hot exciton” mechanism to date. These results could shed light on the design principles for “hot exciton” materials and inspire the development of next-generation high-performance OLEDs. © 2020 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

As the congener of organic light-emitting diodes, polymeric light-emitting diodes (PLEDs) possess a number of distinct merits, such as a low-cost wet fabrication process, which make them applicable in large-area flexible display and lighting fields. However, most emissive polymers used in PLEDs suffer from the aggregation-caused quenching (ACQ) effect, which makes the device show large efficiency roll-off. In this work, two polymers, pTPE-DPA-Cz and pTPE-DPA-Flu, featuring aggregation-induced emission (AIE) characteristics were facilely synthesized through Suzuki-Miyaura polycoupling reaction by incorporating the AIE unit of TPE-DPA in their main chains. The resultant polymers possess good film-forming ability, excellent thermal stability and high photoluminescence quantum yields (PLQYs) in their film states, facilitating the fabrication of PLEDs through a solution process. Indeed, the PLEDs using pTPE-DPA-Cz and pTPE-DPA-Flu as emitting layers (EMLs) could achieve a maximum external quantum efficiency (EQE) of 3.26% (doped EML) and current efficiency of 3.69 cd A(-1) (non-doped EML). Notably, all the devices exhibit a quite low efficiency roll-off. This work indicates that AIE polymers are ideal candidates for the construction of high performance PLEDs with low efficiency roll-off.

Planarized intramolecular charge transfer(PLICT) state can facilitate the fluorescence process thanks to the relative excellent planarity. Recently, we have discovered that the excited state quinone-conformation induced planarization(ESQIP) occurring on tetraphenylpyrazine(TPP) based derivatives could furnish them with PLICT feature. Unlike to the well-known intramolecular charge transfer, strengthening the electron-donating nature on the donor(D) moiety did not impair the PLICT. The calculation results showed that planarization of the TPP based compounds scarcely accompanied with energy wastage while amount of energy was required for the torsion on geometries. In the polar solvents, the energy consumption for planarization could further decrease, but that for twisting structure would increase. To take advantage of the transformation of the frontier orbitals’ distribution, the PLICT type materials would perform a potential application on organic light-emitting diodes(OLEDs). © 2019, Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH.

Pure organic materials with circularly polarized luminescence (CPL) and delayed fluorescence have gained increasing interest from academic and technological areas. To enhance the solid-state emission and exciton utilization in chiral optoelectronic devices, a synthetic strategy to impart conjugated polymers with CPL and aggregation-induced delayed fluorescence was proposed. Herein, two conjugated macromolecules with electron-donating poly(carbazole-ran-acridine) backbones, electron-withdrawing dibenzothiophen-2-yl(phenyl)methanone, and chiral alanine moieties were designed and synthesized. Their neat films exhibited strong green emission with quantum yields of 6.7 and 10.3% and delayed fluorescence with a lifetime of 1.358 and 1.366 μs, respectively. Both the Cotton effect and CPL with a dissymmetry factor of −2.01 × 10–3 and −1.39 × 10–3 were determined in the solid state. Such unique conjugated polymers were employed as solution-processed emitting layers in organic light emitting diodes, which displayed a maximum brightness of 1477 cd/m2 and maximum current efficiency of 2.52 cd/A.

For the constant demand of organic light-emitting diodes (OLEDs) with high efficiency, long lifetime, and low cost for display and lighting applications, the development of high-performance organic electroluminescence materials is key. Aggregation-induced emission (AIE) luminogens (AIEgens) provide a promising choice for their excellent performance in nondoped devices. Here we report a multifunctional deep blue AIE material, which can be used not only as an excellent blue emitter but also as a good host of green/orange/red phosphors. A deep blue nondoped OLED with a CIEy of 0.08 and high external quantum efficiency (EQE) of 7.0% is achieved. Furthermore, a series of green/orange/red phosphorescent OLEDs with high efficiency and low roll-off are obtained. Impressively, hybrid white OLEDs (WOLEDs) based on the deep blue AIEgen exhibit simultaneously high CRI (>90), excellent efficiency (EQE(max) > 25%, PEmax = 99.9 lm W-1 for two-color WOLEDs, PEmax = 60.7 lm W-1 for four-color WOLEDs), low roll-off (PE1000nit = 72.1 lm W-1 for two-color WOLEDs, PE1000nit = 43.5 lm W-1 for four-color WOLEDs), and superior stable color, indicative of the multifunction of AIEgens. Accordingly, this work opens a new direction for achieving high-performance OLEDs, particularly offering a smart but simple way to depress the efficiency roll-off and reduce the cost of OLEDs for practical applications.

OLEDs with high efficiency and low roll-off are urgently needed to meet the constantly increasing commercial demands for white organic light-emitting diodes (WOLEDs) in lighting industry applications. To enhance efficiency and decrease WOLED roll-off, complicated doping technologies are employed, which result in an additional increase in costs. Herein, a deep-blue-light molecule (3TPA-CN) with aggregation-induced emission (AIE) is introduced as blue emitter and phosphor host to fabricate WOLEDs. By optimizing the emission zones, high efficiency and low roll-off hybrid WOLEDs are achieved. The maximum forward-viewing power and external quantum efficiencies reach 86.7 lm W −1 and 22.3%, and remain 59.2 lm W −1 and 19.6% at a luminance of 1000 cd m −2 , fully exhibiting the prospect of AIE molecules as a promising electroluminescence material for the fabrication of high-performance WOLEDs. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

For the constant demand of organic light-emitting diodes (OLEDs) with high efficiency, long lifetime, and low cost for display and lighting applications, the development of high-performance organic electroluminescence materials is key. Aggregation-induced emission (AIE) luminogens (AIEgens) provide a promising choice for their excellent performance in nondoped devices. Here we report a multifunctional deep blue AIE material, which can be used not only as an excellent blue emitter but also as a good host of green/orange/red phosphors. A deep blue nondoped OLED with a CIEy of 0.08 and high external quantum efficiency (EQE) of 7.0% is achieved. Furthermore, a series of green/orange/red phosphorescent OLEDs with high efficiency and low roll-off are obtained. Impressively, hybrid white OLEDs (WOLEDs) based on the deep blue AIEgen exhibit simultaneously high CRI (>90), excellent efficiency (EQE(max) > 25%, PEmax = 99.9 lm W-1 for two-color WOLEDs, PEmax = 60.7 lm W-1 for four-color WOLEDs), low roll-off (PE1000nit = 72.1 lm W-1 for two-color WOLEDs, PE1000nit = 43.5 lm W-1 for four-color WOLEDs), and superior stable color, indicative of the multifunction of AIEgens. Accordingly, this work opens a new direction for achieving high-performance OLEDs, particularly offering a smart but simple way to depress the efficiency roll-off and reduce the cost of OLEDs for practical applications.

OLEDs with high efficiency and low roll-off are urgently needed to meet the constantly increasing commercial demands for white organic light-emitting diodes (WOLEDs) in lighting industry applications. To enhance efficiency and decrease WOLED roll-off, complicated doping technologies are employed, which result in an additional increase in costs. Herein, a deep-blue-light molecule (3TPA-CN) with aggregation-induced emission (AIE) is introduced as blue emitter and phosphor host to fabricate WOLEDs. By optimizing the emission zones, high efficiency and low roll-off hybrid WOLEDs are achieved. The maximum forward-viewing power and external quantum efficiencies reach 86.7 lm W −1 and 22.3%, and remain 59.2 lm W −1 and 19.6% at a luminance of 1000 cd m −2 , fully exhibiting the prospect of AIE molecules as a promising electroluminescence material for the fabrication of high-performance WOLEDs. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

For the constant demand of organic light-emitting diodes (OLEDs) with high efficiency, long lifetime, and low cost for display and lighting applications, the development of high-performance organic electroluminescence materials is key. Aggregation-induced emission (AIE) luminogens (AIEgens) provide a promising choice for their excellent performance in nondoped devices. Here we report a multifunctional deep blue AIE material, which can be used not only as an excellent blue emitter but also as a good host of green/orange/red phosphors. A deep blue nondoped OLED with a CIEy of 0.08 and high external quantum efficiency (EQE) of 7.0% is achieved. Furthermore, a series of green/orange/red phosphorescent OLEDs with high efficiency and low roll-off are obtained. Impressively, hybrid white OLEDs (WOLEDs) based on the deep blue AIEgen exhibit simultaneously high CRI (>90), excellent efficiency (EQE(max) > 25%, PEmax = 99.9 lm W-1 for two-color WOLEDs, PEmax = 60.7 lm W-1 for four-color WOLEDs), low roll-off (PE1000nit = 72.1 lm W-1 for two-color WOLEDs, PE1000nit = 43.5 lm W-1 for four-color WOLEDs), and superior stable color, indicative of the multifunction of AIEgens. Accordingly, this work opens a new direction for achieving high-performance OLEDs, particularly offering a smart but simple way to depress the efficiency roll-off and reduce the cost of OLEDs for practical applications.

Development of highly efficient circularly polarized organic light‐emitting diodes (CPOLEDs) has gained increasing interest as they show improved luminous efficiency and high contract 3D images in OLED displays. In this work, a series of binaphthalene‐containing luminogenic enantiomers with aggregation‐induced emission (AIE) and delayed fluorescence properties is designed and synthesized. These molecules can emit from green to red light depending on the solvent polarity due to the twisted intramolecular charge transfer effect. However, their solid powders show bright light emissions, demonstrating a phenomenon of AIE. All the molecules exhibit Cotton effects and circularly polarized luminescence in toluene solution and films. Multilayer CPOLEDs using the doped and neat films of the molecules as emitting layers are fabricated, which exhibit high external quantum efficiency of up to 9.3% and 3.5% and electroluminescence dissymmetry factor (gEL) of up to +0.026/−0.021 and +0.06/−0.06, respectively. Compared with doped CPOLEDs, the nondoped ones show higher gEL and much smaller current efficiency roll‐off due to the stronger AIE effect. By altering the donor unit, the electroluminescence maximum of the doped film can vary from 493 to 571 nm. As far as it is known, this is the first example of efficient CPOLEDs based on small chiral organic molecules.

Development of highly efficient circularly polarized organic light‐emitting diodes (CPOLEDs) has gained increasing interest as they show improved luminous efficiency and high contract 3D images in OLED displays. In this work, a series of binaphthalene‐containing luminogenic enantiomers with aggregation‐induced emission (AIE) and delayed fluorescence properties is designed and synthesized. These molecules can emit from green to red light depending on the solvent polarity due to the twisted intramolecular charge transfer effect. However, their solid powders show bright light emissions, demonstrating a phenomenon of AIE. All the molecules exhibit Cotton effects and circularly polarized luminescence in toluene solution and films. Multilayer CPOLEDs using the doped and neat films of the molecules as emitting layers are fabricated, which exhibit high external quantum efficiency of up to 9.3% and 3.5% and electroluminescence dissymmetry factor (gEL) of up to +0.026/−0.021 and +0.06/−0.06, respectively. Compared with doped CPOLEDs, the nondoped ones show higher gEL and much smaller current efficiency roll‐off due to the stronger AIE effect. By altering the donor unit, the electroluminescence maximum of the doped film can vary from 493 to 571 nm. As far as it is known, this is the first example of efficient CPOLEDs based on small chiral organic molecules.

Development of highly efficient circularly polarized organic light‐emitting diodes (CPOLEDs) has gained increasing interest as they show improved luminous efficiency and high contract 3D images in OLED displays. In this work, a series of binaphthalene‐containing luminogenic enantiomers with aggregation‐induced emission (AIE) and delayed fluorescence properties is designed and synthesized. These molecules can emit from green to red light depending on the solvent polarity due to the twisted intramolecular charge transfer effect. However, their solid powders show bright light emissions, demonstrating a phenomenon of AIE. All the molecules exhibit Cotton effects and circularly polarized luminescence in toluene solution and films. Multilayer CPOLEDs using the doped and neat films of the molecules as emitting layers are fabricated, which exhibit high external quantum efficiency of up to 9.3% and 3.5% and electroluminescence dissymmetry factor (gEL) of up to +0.026/−0.021 and +0.06/−0.06, respectively. Compared with doped CPOLEDs, the nondoped ones show higher gEL and much smaller current efficiency roll‐off due to the stronger AIE effect. By altering the donor unit, the electroluminescence maximum of the doped film can vary from 493 to 571 nm. As far as it is known, this is the first example of efficient CPOLEDs based on small chiral organic molecules.

Recently, a family of interesting analytical brane solutions were found in $f(R)$ gravity with $f(R)=R+\alpha R^2$ in Ref. [Phys. Lett. B 729, 127 (2014)]. In these solutions, inner brane structure can be turned on by tuning the value of the parameter $\alpha$. In this paper, we investigate how the parameter $\alpha$ affects the localization and the quasilocalization of the tensorial gravitons around these solutions. It is found that, in a range of $\alpha$, despite the brane has an inner structure, there is no graviton resonance. However, in some other regions of the parameter space, although the brane has no internal structure, the effective potential for the graviton KK modes has a singular structure, and there exists a series of graviton resonant modes. The contribution of the massive graviton KK modes to the Newton's law of gravity is discussed shortly., Comment: v2: 10 pages, 8 figures, to be published in EPJC

Recently, a family of interesting analytical brane solutions were found in $f(R)$ gravity with $f(R)=R+\alpha R^2$ in Ref. [Phys. Lett. B 729, 127 (2014)]. In these solutions, inner brane structure can be turned on by tuning the value of the parameter $\alpha$. In this paper, we investigate how the parameter $\alpha$ affects the localization and the quasilocalization of the tensorial gravitons around these solutions. It is found that, in a range of $\alpha$, despite the brane has an inner structure, there is no graviton resonance. However, in some other regions of the parameter space, although the brane has no internal structure, the effective potential for the graviton KK modes has a singular structure, and there exists a series of graviton resonant modes. The contribution of the massive graviton KK modes to the Newton's law of gravity is discussed shortly., Comment: v2: 10 pages, 8 figures, to be published in EPJC

It is known that by introducing the Yukawa coupling between the fermion and the background scalar field, a bulk spin-half fermion can be localized on general Randall-Sundrum braneworlds generated by a kinklike background scalar. However, this localization mechanism does not work anymore for Randall-Sundrum braneworlds generated by a scalar whose configuration is an even function of the extra dimension. In this paper, we present a new localization mechanism for spin-half fermions for such a class of braneworld models, in which extra dimension has the topology $S^1/Z_2$. By two examples, it is shown that the new localization mechanism produces interesting results. In the first model with the brane generated by two scalars, the zero mode of the left-handed fermion is localized on the brane and there is a mass gap between the fermion zero mode and excited KK modes. In the second model with the brane generated by a dilaton scalar, the zero mode of the left- or right-chiral fermion can be localized on the brane and there is no mass gap., Comment: 8 pages, 2 figures

It is known that by introducing the Yukawa coupling between the fermion and the background scalar field, a bulk spin-half fermion can be localized on general Randall-Sundrum braneworlds generated by a kinklike background scalar. However, this localization mechanism does not work anymore for Randall-Sundrum braneworlds generated by a scalar whose configuration is an even function of the extra dimension. In this paper, we present a new localization mechanism for spin-half fermions for such a class of braneworld models, in which extra dimension has the topology $S^1/Z_2$. By two examples, it is shown that the new localization mechanism produces interesting results. In the first model with the brane generated by two scalars, the zero mode of the left-handed fermion is localized on the brane and there is a mass gap between the fermion zero mode and excited KK modes. In the second model with the brane generated by a dilaton scalar, the zero mode of the left- or right-chiral fermion can be localized on the brane and there is no mass gap., Comment: 8 pages, 2 figures

Extending the carotenoid pathway to astaxanthin in plants is of scientific and industrial interest. However, expression of a microbial beta-carotene ketolase (BKT) that catalyses the formation of ketocarotenoids in transgenic plants typically results in low levels of astaxanthin. The low efficiency of BKTs in ketolating zeaxanthin to astaxanthin is proposed to be the major limitation for astaxanthin accumulation in engineered plants. To verify this hypothesis, several algal BKTs were functionally characterized using an Escherichia coli system and three BKTs were identified, with high (up to 85%), moderate (~38%), and low (~1%) conversion rate from zeaxanthin to astaxanthin from Chlamydomonas reinhardtii (CrBKT), Chlorella zofingiensis (CzBKT), and Haematococcus pluvialis (HpBKT3), respectively. Transgenic Arabidopsis thaliana expressing the CrBKT developed orange leaves which accumulated astaxanthin up to 2 mg g -1 dry weight with a 1.8-fold increase in total carotenoids. In contrast, the expression of CzBKT resulted in much lower astaxanthin content (0.24 mg g -1 dry weight), whereas HpBKT3 was unable to mediate synthesis of astaxanthin in A. thaliana. The none-native astaxanthin was found mostly in a free form integrated into the light-harvesting complexes of photosystem II in young leaves but in esterified forms in senescent leaves. The alteration of carotenoids did not affect chlorophyll content, plant growth, or development significantly. The astaxanthin-producing plants were more tolerant to high light as shown by reduced lipid peroxidation. This study advances a decisive step towards the utilization of plants for the production of high-value astaxanthin. Keywords: Arabidopsis thaliana, astaxanthin, beta-carotene ketolase, carotenoid, Haematococcus pluvialis

SaPIN2a encodes a proteinase inhibitor in nightshade (Solanum americanum), which is specifically localized to the enucleate sieve elements. It has been proposed to play an important role in phloem development by regulating proteolysis in sieve elements. In this study, we purified and characterized native SaPIN2a from nightshade stems and recombinant SaPIN2a expressed in Escherichia coli. Purified native SaPIN2a was found as a charge isomer family of homodimers, and was weakly glycosylated. Native SaPIN2a significantly inhibited serine proteinases such as trypsin, chymotrypsin, and subtilisin, with the most potent inhibitory activity on subtilisin. It did not inhibit cysteine proteinase papain and aspartic proteinase cathepsin D. Recombinant SaPIN2a had a strong inhibitory effect on chymotrypsin, but its inhibitory activities toward trypsin and especially toward subtilisin were greatly reduced. In addition, native SaPIN2a can effectively inhibit midgut trypsin-like activities from Trichoplusia ni and Spodoptera litura larvae, suggesting a potential for the production of insect-resistant transgenic plants. (C) 2007 Published by Elsevier Masson SAS.

SaPIN2a encodes a proteinase inhibitor in nightshade (Solanum americanum), which is specifically localized to the enucleate sieve elements. It has been proposed to play an important role in phloem development by regulating proteolysis in sieve elements. In this study, we purified and characterized native SaPIN2a from nightshade stems and recombinant SaPIN2a expressed in Escherichia coli. Purified native SaPIN2a was found as a charge isomer family of homodimers, and was weakly glycosylated. Native SaPIN2a significantly inhibited serine proteinases such as trypsin, chymotrypsin, and subtilisin, with the most potent inhibitory activity on subtilisin. It did not inhibit cysteine proteinase papain and aspartic proteinase cathepsin D. Recombinant SaPIN2a had a strong inhibitory effect on chymotrypsin, but its inhibitory activities toward trypsin and especially toward subtilisin were greatly reduced. In addition, native SaPIN2a can effectively inhibit midgut trypsin-like activities from Trichoplusia ni and Spodoptera litura larvae, suggesting a potential for the production of insect-resistant transgenic plants. (C) 2007 Published by Elsevier Masson SAS.

SaPIN2a encodes a proteinase inhibitor in nightshade (Solanum americanum), which is specifically localized to the enucleate sieve elements. It has been proposed to play an important role in phloem development by regulating proteolysis in sieve elements. In this study, we purified and characterized native SaPIN2a from nightshade stems and recombinant SaPIN2a expressed in Escherichia coli. Purified native SaPIN2a was found as a charge isomer family of homodimers, and was weakly glycosylated. Native SaPIN2a significantly inhibited serine proteinases such as trypsin, chymotrypsin, and subtilisin, with the most potent inhibitory activity on subtilisin. It did not inhibit cysteine proteinase papain and aspartic proteinase cathepsin D. Recombinant SaPIN2a had a strong inhibitory effect on chymotrypsin, but its inhibitory activities toward trypsin and especially toward subtilisin were greatly reduced. In addition, native SaPIN2a can effectively inhibit midgut trypsin-like activities from Trichoplusia ni and Spodoptera litura larvae, suggesting a potential for the production of insect-resistant transgenic plants. (C) 2007 Published by Elsevier Masson SAS.