Human aldo-keto reductase 1D1 (AKR1D1) and AKR1C enzymes are essential for bile acid biosynthesis... more Human aldo-keto reductase 1D1 (AKR1D1) and AKR1C enzymes are essential for bile acid biosynthesis and steroid hormone metabolism. AKR1D1 catalyzes the 5β-reduction of Îâ´-3-ketosteroids, whereas AKR1C enzymes are hydroxysteroid dehydrogenases (HSDs). These enzymes share high sequence identity and catalyze 4-pro-(R)-hydride transfer from NADPH to an electrophilic carbon but differ in that one residue in the conserved AKR catalytic tetrad, His120
Human steroid 5-reductase (aldo-keto reductase 1D1) catalyzes the stereospecific NADPH-dependent... more Human steroid 5-reductase (aldo-keto reductase 1D1) catalyzes the stereospecific NADPH-dependent reduction of the C4-C5 double bond of 4 -ketosteroids to yield an A/B cis-ring junction. This cisconfiguration is crucial for bile acid biosynthesis and plays important roles in steroid metabolism. The biochemical properties of the enzyme have not been thoroughly studied and conflicting data have been reported, partially due to the lack of highly homogeneous protein. In the present study, we systematically determined the substrate specificity of homogeneous human recombinant AKR1D1 using C18, C19, C21, and C27 4 -ketosteroids and assessed the pH-rate dependence of the enzyme. Our results show that AKR1D1 proficiently reduced all the steroids tested at physiological pH, indicating AKR1D1 is the only enzyme necessary for all the 5-steroid metabolites present in humans. Substrate inhibition was observed with C18 to C21 steroids provided that the C11 position was unsubstituted. This structure activity relationship can be explained by the existence of a small alternative substrate binding pocket revealed by the AKR1D1 crystal structure. Non-steroidal anti-inflammatory drugs which are potent inhibitors of the related AKR1C enzymes do not inhibit AKR1D1. By contrast chenodeoxycholate and ursodeoxycholate were found to be potent non-competitive inhibitors suggesting that bile-acids may regulate their own synthesis at the level of AKR1D1 inhibition.
ABSTRACT We present a first-principles computer code package (ABACUS) that is based on density fu... more ABSTRACT We present a first-principles computer code package (ABACUS) that is based on density functional theory and numerical atomic basis sets. Theoretical foundations and numerical techniques used in the code are described, with focus on the accuracy and transferability of the hierarchical atomic basis sets as generated using a scheme proposed by Chen, Guo and He [J. Phys.:Condens. Matter \textbf{22}, 445501 (2010)]. Benchmark results are presented for a variety of systems include molecules, solids, surfaces, and defects. All results show that the ABACUS package with its associated atomic basis sets is an efficient and reliable tool for simulating both small and large-scale materials.
Proceedings 1992 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 1992
... This work was supporbedin part of t.lie Linited States Postal Service through cont,ract numbe... more ... This work was supporbedin part of t.lie Linited States Postal Service through cont,ract number 104230-S4D-0962 and task or-der 104230-8GM-3990 t,o the C ... ter-based st8a.t,ist,ics is first coniput,ed from t,he given dict,ionary, aiid t,lieii re-fined 11)- t,lie brea.k-point proba.hilit,y ...
The surface modification of LEDs based on GaAs is realized by super-aligned multiwalled carbon na... more The surface modification of LEDs based on GaAs is realized by super-aligned multiwalled carbon nanotube (SACNT) networks as etching masks. The surface morphology of SACNT networks is transferred to the GaAs. It is found that the light output power of LEDs based on GaAs with a nanostructured surface morphology is greatly enhanced with the electrical power unchanged.
International Journal of Pattern Recognition and Artificial Intelligence, 2015
ABSTRACT Traditional methods for automatic recognition of container code in visual images are bas... more ABSTRACT Traditional methods for automatic recognition of container code in visual images are based on segmentation and recognition of isolated characters. However, when the segment fails to separate each character from the others, those methods will not function properly. Sometimes the container code characters are printed or arranged very closely, which makes it a challenge to isolate each character. To address this issue, a new framework for automatic container code recognition (ACCR) in visual images is proposed in this paper. In this framework, code-character regions are first located by applying a horizontal high-pass filter and scan line analysis. Then, character blocks are extracted from the code-character regions and further classified into two categories, i.e. single-character block and multi-character block. Finally, a segmentation-based approach is implemented for recognition of the characters in single-character blocks, and a hidden Markov model (HMM)-based method is proposed for the multi-character blocks. The experimental results demonstrate the effectiveness of the proposed method, which can successfully recognize the container code with closely arranged characters.
This paper presents a data compression method that can achieve a very large compression ratio for... more This paper presents a data compression method that can achieve a very large compression ratio for radar pulse trains that are to be used for time-difference-of-arrival/frequency-difference-ofarrival (TDOA/FDOA) multiple-platform emitter location; this method exploits pulse-to-pulse redundancy to get a compression ratio much higher than possible using standard compression methods. We show how to use (i) the ability of the singular value decomposition (SVD) to exploit redundancy between radar pulses, and (ii) a Fisher information-based distortion criterion to enable elimination of pulses that are negligible to the FDOA estimation tasks. To enable the SVD to effectively remove the redundancy it is necessary to first optimally gate the pulses and place them in the rows of a matrix and then align the pulses to arrive at a matrix that is close to having rank of one. Finally, we suggest reasonable coding schemes for the information to be sent and assess the achievable compression level.
2009 Sixth International Conference on Fuzzy Systems and Knowledge Discovery, 2009
ABSTRACT An algorithm was proposed to recognize characters based on optimal wavelet packet (WP), ... more ABSTRACT An algorithm was proposed to recognize characters based on optimal wavelet packet (WP), Zernike moments and fuzzy integral. At first, optimal wavelet decomposition of the given character image was gotten by fuzzy rules, and characters in training set were put into n subspaces through optimal wavelet packet. Then, for each subspace, the Zernike moments were employed to get the mean membership grades of test characters with respect to each class in training set, separately. At last, the final class that test characters belonged to was declared according to aggregating the above membership grades and the fuzzy measures using fuzzy integral. The experiment proved that the proposed algorithm had a better recognition effect.
21st International Conference on Optical Fiber Sensors, 2011
Two DFB semiconductor lasers are adopted as master and slave lasers to investigate the properties... more Two DFB semiconductor lasers are adopted as master and slave lasers to investigate the properties of the weak injection locked DFB laser, such as the stable locking range, the phase noise and the power stability. A Brillouin/erbium fiber laser pumped by the master DFB laser is injected into the slave DFB laser to validate the improvements of power stability and
Funding: The work for composition of this article is supported by NIH grants R01DE018248, R01EB00... more Funding: The work for composition of this article is supported by NIH grants R01DE018248, R01EB009663 and RC2DE020767 (to J.J.M.). Conflict of interest: Columbia University is the owner of patents for several regenerative endodontic agents and methods on behalf of Dr Jeremy Mao's laboratory.
To compare the radiation-induced temporal lobe injury (TLI) in patients with nasopharyngeal carci... more To compare the radiation-induced temporal lobe injury (TLI) in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT) or two-dimensional conventional radiotherapy (2D-CRT). 1276 cases of NPC treated with IMRT or 2D-CRT were retrospectively reviewed. A diagnosis of TLI was made on follow-up magnetic resonance imaging (MRI). The crude incidence of TLI was 7.5% and 10.8% (P = 0.048), and the actuarial 5-year incidence was 16% and 34.9% (P<0.001) for the IMRT and 2D-CRT groups, respectively. Multivariate analysis revealed both T stage (P<0.001) and radiation technique (P<0.001) as independent predictors. Patients with T1, T2 and T3 disease had a significantly higher risk when treated with 2D-CRT (P = 0.005, 0.016,…
ACM International Conference Proceeding Series, 2012
Engaging children born in the digital age with traditional culture practices is a pedagogical and... more Engaging children born in the digital age with traditional culture practices is a pedagogical and a technological challenge. In this paper we describe Ilha Musical, an interactive panoramic experience designed to foster appreciation of traditional Madeiran cultural practices in children from the island and abroad. The design employs a rhythm game in which children engage in traditional folk music and song while being exposed to visuals of the landscape, architecture, dance and other cultural motifs. We conclude with an eye tracking and scene analysis showing the success of the game in using competition and cooperation as a means of engaging the children with each other as well as with the narrative, the physical display and interface elements.
Dental follicle gives rise to one or several tissues of the periodontium including the periodonta... more Dental follicle gives rise to one or several tissues of the periodontium including the periodontal ligament, cementum and/or alveolar bone. Whether Wnt5a is expressed in the postnatal periodontium or regulates dental follicle stem/progenitor cells is unknown. Dental follicle stem/progenitor cells were isolated from postnatal day 1 (p1) to p11 from rat mandibular first molars. Immunolocalization mapped Wnt5a expression in the alveolar bone, periodontal ligament, and the developing ameloblast and odontoblast layers. Mononucleated and adherent cells were isolated from p7 dental follicle. Wnt5a was overexpressed in dental follicle stem/progenitor cells to study their proliferation, osteogenic differentiation and migration behavior, with subpopulations of native dental follicle stem/progenitor cells as controls, using real-time PCR (Taqman), Lenti-viral transfection, Western blotting and immunofluorescence. Wnt5a was expressed consistently in p1 to p11 rat peridontium. Native, p7 dental ...
To investigate the protective effect and mechanism of rebamipide on small intestinal permeability... more To investigate the protective effect and mechanism of rebamipide on small intestinal permeability induced by diclofenac in mice. Diclofenac (2.5 mg/kg) was administered once daily for 3 d orally. A control group received the vehicle by gavage. Rebamipide (100 mg/kg, 200 mg/kg, 400 mg/kg) was administered intragastrically once a day for 3 d 4 h after diclofenac administration. Intestinal permeability was evaluated by Evans blue and the FITC-dextran method. The ultrastructure of the mucosal barrier was evaluated by transmission electron microscopy (TEM). Mitochondrial function including mitochondrial swelling, mitochondrial membrane potential, mitochondrial nicotinamide adenine dinucleotide-reduced (NADH) levels, succinate dehydrogenase (SDH) and ATPase activities were measured. Small intestinal mucosa was collected for assessment of malondialdehyde (MDA) content and myeloperoxidase (MPO) activity. Compared with the control group, intestinal permeability was significantly increased in the diclofenac group, which was accompanied by broken tight junctions, and significant increases in MDA content and MPO activity. Rebamipide significantly reduced intestinal permeability, improved inter-cellular tight junctions, and was associated with decreases in intestinal MDA content and MPO activity. At the mitochondrial level, rebamipide increased SDH and ATPase activities, NADH level and decreased mitochondrial swelling. Increased intestinal permeability induced by diclofenac can be attenuated by rebamipide, which partially contributed to the protection of mitochondrial function.
Cell transplantation has been well explored for cartilage regeneration. We recently showed that t... more Cell transplantation has been well explored for cartilage regeneration. We recently showed that the entire articular surface of a synovial joint can regenerate by endogenous cell homing and without cell transplantation. However, the sources of endogenous cells that regenerate articular cartilage remain elusive. Here, we studied whether cytokines not only chemotactically recruit adipose stem cells (ASCs), mesenchymal stem cells (MSCs), and synovium stem cells (SSCs) but also induce chondrogenesis of the recruited cells. Recombinant human transforming growth factor-β3 (TGF-β3; 100 ng) and/or recombinant human stromal derived factor-1β (SDF-1β; 100 ng) was control released into an acellular collagen sponge cube with underlying ASCs, MSCs, or SSCs in monolayer culture. Although all cell types randomly migrated into the acellular collagen sponge cube, TGF-β3 and/or SDF-1β recruited significantly more cells than the cytokine-free control group. In 6 wk, TGF-β3 alone recruited substantial numbers of ASCs (558±65) and MSCs (302±52), whereas codelivery of TGF-β3 and SDF-1β was particularly chemotactic to SSCs (400±120). Proliferation of the recruited cells accounted for some, but far from all, of the observed cellularity. TGF-β3 and SDF-1β codelivery induced significantly higher aggrecan gene expression than the cytokine-free group for ASCs, MSCs, and SSCs. Type II collagen gene expression was also significantly higher for ASCs and SSCs by SDF-1 and TGF-β3 codelivery. Remarkably, the expression of aggrecan and type II collagen was detected among all cell types. Thus, homing of multiple stem/progenitor cell populations may potentially serve as an alternative or adjunctive approach to cell transplantation for cartilage regeneration.
Objective: To determine the specificity and efficiency of the tamoxifen (TM)-induced Cre-recombin... more Objective: To determine the specificity and efficiency of the tamoxifen (TM)-induced Cre-recombination in articular chondrocytes of adult Col2a1-CreER T2 transgenic mice.
We present a low noise single-frequency and single-polarization distributed Bragg reflector fiber... more We present a low noise single-frequency and single-polarization distributed Bragg reflector fiber laser at 1083 nm by using a 1.8 cm long newly developed ytterbium-doped phosphate single mode glass fiber. The maximum output power is more than 100 mW with a slope efficiency of >29.6%. The signal to noise ratio is higher than 61 dB and the laser linewidth of less than 2 kHz is estimated. The obtained relative intensity noise for frequencies of over 4.0 MHz is less than −150 dB∕Hz, which approaches the shot noise limit. The achieved linear polarization extinction ratio is more than 30 dB.
Human aldo-keto reductase 1D1 (AKR1D1) and AKR1C enzymes are essential for bile acid biosynthesis... more Human aldo-keto reductase 1D1 (AKR1D1) and AKR1C enzymes are essential for bile acid biosynthesis and steroid hormone metabolism. AKR1D1 catalyzes the 5β-reduction of Îâ´-3-ketosteroids, whereas AKR1C enzymes are hydroxysteroid dehydrogenases (HSDs). These enzymes share high sequence identity and catalyze 4-pro-(R)-hydride transfer from NADPH to an electrophilic carbon but differ in that one residue in the conserved AKR catalytic tetrad, His120
Human steroid 5-reductase (aldo-keto reductase 1D1) catalyzes the stereospecific NADPH-dependent... more Human steroid 5-reductase (aldo-keto reductase 1D1) catalyzes the stereospecific NADPH-dependent reduction of the C4-C5 double bond of 4 -ketosteroids to yield an A/B cis-ring junction. This cisconfiguration is crucial for bile acid biosynthesis and plays important roles in steroid metabolism. The biochemical properties of the enzyme have not been thoroughly studied and conflicting data have been reported, partially due to the lack of highly homogeneous protein. In the present study, we systematically determined the substrate specificity of homogeneous human recombinant AKR1D1 using C18, C19, C21, and C27 4 -ketosteroids and assessed the pH-rate dependence of the enzyme. Our results show that AKR1D1 proficiently reduced all the steroids tested at physiological pH, indicating AKR1D1 is the only enzyme necessary for all the 5-steroid metabolites present in humans. Substrate inhibition was observed with C18 to C21 steroids provided that the C11 position was unsubstituted. This structure activity relationship can be explained by the existence of a small alternative substrate binding pocket revealed by the AKR1D1 crystal structure. Non-steroidal anti-inflammatory drugs which are potent inhibitors of the related AKR1C enzymes do not inhibit AKR1D1. By contrast chenodeoxycholate and ursodeoxycholate were found to be potent non-competitive inhibitors suggesting that bile-acids may regulate their own synthesis at the level of AKR1D1 inhibition.
ABSTRACT We present a first-principles computer code package (ABACUS) that is based on density fu... more ABSTRACT We present a first-principles computer code package (ABACUS) that is based on density functional theory and numerical atomic basis sets. Theoretical foundations and numerical techniques used in the code are described, with focus on the accuracy and transferability of the hierarchical atomic basis sets as generated using a scheme proposed by Chen, Guo and He [J. Phys.:Condens. Matter \textbf{22}, 445501 (2010)]. Benchmark results are presented for a variety of systems include molecules, solids, surfaces, and defects. All results show that the ABACUS package with its associated atomic basis sets is an efficient and reliable tool for simulating both small and large-scale materials.
Proceedings 1992 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 1992
... This work was supporbedin part of t.lie Linited States Postal Service through cont,ract numbe... more ... This work was supporbedin part of t.lie Linited States Postal Service through cont,ract number 104230-S4D-0962 and task or-der 104230-8GM-3990 t,o the C ... ter-based st8a.t,ist,ics is first coniput,ed from t,he given dict,ionary, aiid t,lieii re-fined 11)- t,lie brea.k-point proba.hilit,y ...
The surface modification of LEDs based on GaAs is realized by super-aligned multiwalled carbon na... more The surface modification of LEDs based on GaAs is realized by super-aligned multiwalled carbon nanotube (SACNT) networks as etching masks. The surface morphology of SACNT networks is transferred to the GaAs. It is found that the light output power of LEDs based on GaAs with a nanostructured surface morphology is greatly enhanced with the electrical power unchanged.
International Journal of Pattern Recognition and Artificial Intelligence, 2015
ABSTRACT Traditional methods for automatic recognition of container code in visual images are bas... more ABSTRACT Traditional methods for automatic recognition of container code in visual images are based on segmentation and recognition of isolated characters. However, when the segment fails to separate each character from the others, those methods will not function properly. Sometimes the container code characters are printed or arranged very closely, which makes it a challenge to isolate each character. To address this issue, a new framework for automatic container code recognition (ACCR) in visual images is proposed in this paper. In this framework, code-character regions are first located by applying a horizontal high-pass filter and scan line analysis. Then, character blocks are extracted from the code-character regions and further classified into two categories, i.e. single-character block and multi-character block. Finally, a segmentation-based approach is implemented for recognition of the characters in single-character blocks, and a hidden Markov model (HMM)-based method is proposed for the multi-character blocks. The experimental results demonstrate the effectiveness of the proposed method, which can successfully recognize the container code with closely arranged characters.
This paper presents a data compression method that can achieve a very large compression ratio for... more This paper presents a data compression method that can achieve a very large compression ratio for radar pulse trains that are to be used for time-difference-of-arrival/frequency-difference-ofarrival (TDOA/FDOA) multiple-platform emitter location; this method exploits pulse-to-pulse redundancy to get a compression ratio much higher than possible using standard compression methods. We show how to use (i) the ability of the singular value decomposition (SVD) to exploit redundancy between radar pulses, and (ii) a Fisher information-based distortion criterion to enable elimination of pulses that are negligible to the FDOA estimation tasks. To enable the SVD to effectively remove the redundancy it is necessary to first optimally gate the pulses and place them in the rows of a matrix and then align the pulses to arrive at a matrix that is close to having rank of one. Finally, we suggest reasonable coding schemes for the information to be sent and assess the achievable compression level.
2009 Sixth International Conference on Fuzzy Systems and Knowledge Discovery, 2009
ABSTRACT An algorithm was proposed to recognize characters based on optimal wavelet packet (WP), ... more ABSTRACT An algorithm was proposed to recognize characters based on optimal wavelet packet (WP), Zernike moments and fuzzy integral. At first, optimal wavelet decomposition of the given character image was gotten by fuzzy rules, and characters in training set were put into n subspaces through optimal wavelet packet. Then, for each subspace, the Zernike moments were employed to get the mean membership grades of test characters with respect to each class in training set, separately. At last, the final class that test characters belonged to was declared according to aggregating the above membership grades and the fuzzy measures using fuzzy integral. The experiment proved that the proposed algorithm had a better recognition effect.
21st International Conference on Optical Fiber Sensors, 2011
Two DFB semiconductor lasers are adopted as master and slave lasers to investigate the properties... more Two DFB semiconductor lasers are adopted as master and slave lasers to investigate the properties of the weak injection locked DFB laser, such as the stable locking range, the phase noise and the power stability. A Brillouin/erbium fiber laser pumped by the master DFB laser is injected into the slave DFB laser to validate the improvements of power stability and
Funding: The work for composition of this article is supported by NIH grants R01DE018248, R01EB00... more Funding: The work for composition of this article is supported by NIH grants R01DE018248, R01EB009663 and RC2DE020767 (to J.J.M.). Conflict of interest: Columbia University is the owner of patents for several regenerative endodontic agents and methods on behalf of Dr Jeremy Mao's laboratory.
To compare the radiation-induced temporal lobe injury (TLI) in patients with nasopharyngeal carci... more To compare the radiation-induced temporal lobe injury (TLI) in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT) or two-dimensional conventional radiotherapy (2D-CRT). 1276 cases of NPC treated with IMRT or 2D-CRT were retrospectively reviewed. A diagnosis of TLI was made on follow-up magnetic resonance imaging (MRI). The crude incidence of TLI was 7.5% and 10.8% (P = 0.048), and the actuarial 5-year incidence was 16% and 34.9% (P<0.001) for the IMRT and 2D-CRT groups, respectively. Multivariate analysis revealed both T stage (P<0.001) and radiation technique (P<0.001) as independent predictors. Patients with T1, T2 and T3 disease had a significantly higher risk when treated with 2D-CRT (P = 0.005, 0.016,…
ACM International Conference Proceeding Series, 2012
Engaging children born in the digital age with traditional culture practices is a pedagogical and... more Engaging children born in the digital age with traditional culture practices is a pedagogical and a technological challenge. In this paper we describe Ilha Musical, an interactive panoramic experience designed to foster appreciation of traditional Madeiran cultural practices in children from the island and abroad. The design employs a rhythm game in which children engage in traditional folk music and song while being exposed to visuals of the landscape, architecture, dance and other cultural motifs. We conclude with an eye tracking and scene analysis showing the success of the game in using competition and cooperation as a means of engaging the children with each other as well as with the narrative, the physical display and interface elements.
Dental follicle gives rise to one or several tissues of the periodontium including the periodonta... more Dental follicle gives rise to one or several tissues of the periodontium including the periodontal ligament, cementum and/or alveolar bone. Whether Wnt5a is expressed in the postnatal periodontium or regulates dental follicle stem/progenitor cells is unknown. Dental follicle stem/progenitor cells were isolated from postnatal day 1 (p1) to p11 from rat mandibular first molars. Immunolocalization mapped Wnt5a expression in the alveolar bone, periodontal ligament, and the developing ameloblast and odontoblast layers. Mononucleated and adherent cells were isolated from p7 dental follicle. Wnt5a was overexpressed in dental follicle stem/progenitor cells to study their proliferation, osteogenic differentiation and migration behavior, with subpopulations of native dental follicle stem/progenitor cells as controls, using real-time PCR (Taqman), Lenti-viral transfection, Western blotting and immunofluorescence. Wnt5a was expressed consistently in p1 to p11 rat peridontium. Native, p7 dental ...
To investigate the protective effect and mechanism of rebamipide on small intestinal permeability... more To investigate the protective effect and mechanism of rebamipide on small intestinal permeability induced by diclofenac in mice. Diclofenac (2.5 mg/kg) was administered once daily for 3 d orally. A control group received the vehicle by gavage. Rebamipide (100 mg/kg, 200 mg/kg, 400 mg/kg) was administered intragastrically once a day for 3 d 4 h after diclofenac administration. Intestinal permeability was evaluated by Evans blue and the FITC-dextran method. The ultrastructure of the mucosal barrier was evaluated by transmission electron microscopy (TEM). Mitochondrial function including mitochondrial swelling, mitochondrial membrane potential, mitochondrial nicotinamide adenine dinucleotide-reduced (NADH) levels, succinate dehydrogenase (SDH) and ATPase activities were measured. Small intestinal mucosa was collected for assessment of malondialdehyde (MDA) content and myeloperoxidase (MPO) activity. Compared with the control group, intestinal permeability was significantly increased in the diclofenac group, which was accompanied by broken tight junctions, and significant increases in MDA content and MPO activity. Rebamipide significantly reduced intestinal permeability, improved inter-cellular tight junctions, and was associated with decreases in intestinal MDA content and MPO activity. At the mitochondrial level, rebamipide increased SDH and ATPase activities, NADH level and decreased mitochondrial swelling. Increased intestinal permeability induced by diclofenac can be attenuated by rebamipide, which partially contributed to the protection of mitochondrial function.
Cell transplantation has been well explored for cartilage regeneration. We recently showed that t... more Cell transplantation has been well explored for cartilage regeneration. We recently showed that the entire articular surface of a synovial joint can regenerate by endogenous cell homing and without cell transplantation. However, the sources of endogenous cells that regenerate articular cartilage remain elusive. Here, we studied whether cytokines not only chemotactically recruit adipose stem cells (ASCs), mesenchymal stem cells (MSCs), and synovium stem cells (SSCs) but also induce chondrogenesis of the recruited cells. Recombinant human transforming growth factor-β3 (TGF-β3; 100 ng) and/or recombinant human stromal derived factor-1β (SDF-1β; 100 ng) was control released into an acellular collagen sponge cube with underlying ASCs, MSCs, or SSCs in monolayer culture. Although all cell types randomly migrated into the acellular collagen sponge cube, TGF-β3 and/or SDF-1β recruited significantly more cells than the cytokine-free control group. In 6 wk, TGF-β3 alone recruited substantial numbers of ASCs (558±65) and MSCs (302±52), whereas codelivery of TGF-β3 and SDF-1β was particularly chemotactic to SSCs (400±120). Proliferation of the recruited cells accounted for some, but far from all, of the observed cellularity. TGF-β3 and SDF-1β codelivery induced significantly higher aggrecan gene expression than the cytokine-free group for ASCs, MSCs, and SSCs. Type II collagen gene expression was also significantly higher for ASCs and SSCs by SDF-1 and TGF-β3 codelivery. Remarkably, the expression of aggrecan and type II collagen was detected among all cell types. Thus, homing of multiple stem/progenitor cell populations may potentially serve as an alternative or adjunctive approach to cell transplantation for cartilage regeneration.
Objective: To determine the specificity and efficiency of the tamoxifen (TM)-induced Cre-recombin... more Objective: To determine the specificity and efficiency of the tamoxifen (TM)-induced Cre-recombination in articular chondrocytes of adult Col2a1-CreER T2 transgenic mice.
We present a low noise single-frequency and single-polarization distributed Bragg reflector fiber... more We present a low noise single-frequency and single-polarization distributed Bragg reflector fiber laser at 1083 nm by using a 1.8 cm long newly developed ytterbium-doped phosphate single mode glass fiber. The maximum output power is more than 100 mW with a slope efficiency of >29.6%. The signal to noise ratio is higher than 61 dB and the laser linewidth of less than 2 kHz is estimated. The obtained relative intensity noise for frequencies of over 4.0 MHz is less than −150 dB∕Hz, which approaches the shot noise limit. The achieved linear polarization extinction ratio is more than 30 dB.
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