... M. Rubin, N. Newman, JS Chan, TC Fu, and JT Ross Lawrence Berkeley Laboratory, University of ... more ... M. Rubin, N. Newman, JS Chan, TC Fu, and JT Ross Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (Received 28 ... The Ga and Al sources were WA Technologies Series-3 Knudsen cells, and the magnesium source is a Riber Knudsen cell. ...
2011 IEEE International Conference on High Performance Computing and Communications, 2011
Random numbers are used in a wide variety of applications from simulation and encryption to gambl... more Random numbers are used in a wide variety of applications from simulation and encryption to gambling and clinical trials. A good quality random number generator is an asset for applications like encryption, randomized designs and network and information security. Various mathematical models have been developed in the past to improve the quality of random numbers. It can be construed that in general to obtain random numbers of excellent quality, a complex mathematical model has to be used which can be a performance bottleneck. In this work, we propose a novel technique to implement a True Random Number Generator (TRNG) using sources of uncertainty found within Graphics Processing Units (GPUs) together with histogram equalization to obtain maximum entropy. We evaluate the random numbers generated by our approach using four tests. First, we measure the correlation values between two sequences of random numbers, second, we measure the entropy values, third, we use watermarking, an application used in network security and finally we use Monte Carlo analysis for pi-value calculation. Based on these quality measurements, our method has achieved better results than popular random number generators compared in this work. Furthermore, this approach is a massively scalable solution ideal for high performance computing implementations.
2012 IEEE International Conference on Imaging Systems and Techniques Proceedings, 2012
In ultrasound imaging range resolution is proportional to the bandwidth of the transmitted pulse;... more In ultrasound imaging range resolution is proportional to the bandwidth of the transmitted pulse; however, noise also increases with frequency and forces a compromise in imaging accuracy. By compounding multiple synthetic aperture ultrasound images from different frequencies, both the resolution and signal-to-noise ratio (SNR) can be improved, unlike when averaging multiple scans at a single frequency, which would only increase SNR. This paper describes a technique for frequency compounding of synthetic aperture ultrasound images and a practical test setup is introduced for frequency selection for imaging systems consisting of a single piezoelectric transducer and a variable-frequency pulser. An example is provided in which point-scatterers in water are scanned along a linear path at frequencies of 16 to 21 MHz. The resulting multi-frequency imaging increases peak SNR by 13% more than single-frequency averaging with the same number of scans and reduces the rangedomain support of the point-spread function by 30%.
Proceedings of the 2005 Particle Accelerator Conference, 2005
The LCLS injector is required to provide a 1-nC, 10ps bunch with a normalized rms transverse proj... more The LCLS injector is required to provide a 1-nC, 10ps bunch with a normalized rms transverse projected emittance of less than 1 micron. The LCLS beam is generated and accelerated in a 1.6-cell S-band RF gun at 120 MV/m up to 6 MeV. The gun is followed by two SLAC 3-m S-band accelerator structures to further accelerate the beam to 135 MeV which moves the beam out of the space-charge dominated regime. In the SLAC S-band structures, the RF power feed is through a single coupling-hole (single-feed coupler) which results in a field asymmetry. The time dependent multipole fields in the coupler induce a transverse kick along the bunch and cause the emittance to increase above the LCLS specification. To meet the stringent emittance requirements for the injector, the single-feed couplers will be replaced by a dual-feed racetrack design to minimize the multipole field effects. We will present detailed studies of the multipole fields in the SLAC linac RF coupler and the improvements with the dual-feed ractrack design using the parallel finite element S-parameter solver S3P.
Lafarge Corporation has installed several brands of distributed control systems (DCS) and PLC sys... more Lafarge Corporation has installed several brands of distributed control systems (DCS) and PLC systems in our North American plants. In the past, the system selection criteria focused on state-of-the-art technology, plant experience and availability of local services. This paper describes why, with the rapid change of technology today, Lafarge has moved away from such a strategy, and why the AEG Geamatics B system was selected for our plant at Joppa, Illinois. The emergence of the so-called open-platform, and the evolution of classical DCS suppliers to PLC platforms made this decision possible. Implementation and key features of the AEG system at our Joppa plant are described. Also, issues concerning a corporate automation vision and the potential benefits resulting from standardization in a large organization are examined
Designs for a future X-band linear collider (NLC/GLC) require an rf unit that can produce 450 MW ... more Designs for a future X-band linear collider (NLC/GLC) require an rf unit that can produce 450 MW to feed eight 60 cm accelerator structures. The implementation of this rf unit is envisioned to include a dual-moded SLED-II pulse compression system, with a gain of approximately three at a compression ratio of four, followed by an overmoded transmission and distribution system. We describe the tunnel layout plan for these rf systems. The design, construction, and operation of a prototype system are a focus of the 8-Pack project at SLAC. In its initial phase last fall, powered by four 50 MW X-band klystrons sharing a common 400 kV solid-state modulator, the SLED-II system delivered to a set of loads 400 ns pulses of up to 580 MW. In the next phase, this power will be delivered to the NLCTA beamline and distributed between several structures, through which a bunch train will be accelerated. We describe the layout of this system and the functionality of various overmoded, high-power components which comprise it. We also present data on the cold testing, processing and initial operation of the system, which is setting high-power records in pulsed rf.
We have produced 400 ns rf pulses of greater than 500 MW at 11.424 GHz with an rf system designed... more We have produced 400 ns rf pulses of greater than 500 MW at 11.424 GHz with an rf system designed to demonstrate technology capable of powering a TeV scale electron-positron linear collider (NLC). Power is produced by four 50 MW X-band klystrons run off a common 400 kV solid-state modulator. We present the layout of our system, which includes a dual-moded transmission waveguide system and a dual-moded resonant-line (SLED-II) pulse compression system. Dual-moding of the transmission lines allows power to be directed through a pulse compression path or a bypass path; dual-moding in the pulse compressor allows the delay lines to be about half as long as they otherwise would need to be. We describe the design and performance of various components, including hybrids, directional couplers, power dividers, tapers, mode converters, and loads. These components are mostly overmoded to allow for greater power handling. We also present data on the processing and operation of this system, which is setting high-power records in pulsed rf.
Designs for a future TeV scale electron-positron Xband linear collider (NLC/GLC) require main lin... more Designs for a future TeV scale electron-positron Xband linear collider (NLC/GLC) require main linac units which produce and deliver 450 MW of rf power at 11.424 GHz to eight 60 cm accelerator structures. The design of this rf unit includes a SLED-II pulse compression system with a gain of approximately three at a compression ratio of four, followed by an over-moded transmission and distribution system. We have designed, constructed, and operated such a system as part of the 8-Pack project at SLAC. Four 50 MW X-band klystrons, running off a common 400 kV solid-state modulator, drive a dualmoded SLED-II pulse compression system. The compressed power is delivered to structures in the NLCTA beamline. Four 60 cm accelerator structures are currently installed and powered, with four additional structures and associated high power components available for installation late in 2004. We describe the layout of our system and the various high-power components which comprise it. We also present preliminary data on the processing and initial high-power operation of this system.
Physical Review Special Topics - Accelerators and Beams, 2005
We present a multimode X-band rf pulse compression system suitable for a TeV-scale electron-posit... more We present a multimode X-band rf pulse compression system suitable for a TeV-scale electron-positron linear collider such as the Next Linear Collider (NLC). The NLC main linac operating frequency is 11.424 GHz. A single NLC rf unit is required to produce 400 ns pulses with 475 MW of peak power. Each rf unit should power approximately 5 m of accelerator structures. The rf unit design consists of two 75 MW klystrons and a dual-moded resonant-delay-line pulse compression system that produces a flat output pulse. The pulse compression system components are all overmoded, and most components are designed to operate with two modes. This approach allows high-power-handling capability while maintaining a compact, inexpensive system. We detail the design of this system and present experimental cold test results. We describe the design and performance of various components. The high-power testing of the system is verified using four 50 MW solenoid-focused klystrons run off a common 400 kV solidstate modulator. The system has produced 400 ns rf pulses of greater than 500 MW. We present the layout of our system, which includes a dual-moded transmission waveguide system and a dual-moded resonant line (SLED-II) pulse compression system. We also present data on the processing and operation of this system, which has set high-power records in coherent and phase controlled pulsed rf.
The LCLS injector is required to provide a 1-nC, 10-ps bunch with a normalized rms transverse pro... more The LCLS injector is required to provide a 1-nC, 10-ps bunch with a normalized rms transverse projected emittance of less than 1 micron. The LCLS beam is generated and accelerated in a 1.6-cell S-band RF gun at 120 MV/m up to 6 MeV. The gun is followed by two SLAC 3-m S-band accelerator structures to further accelerate the beam to 135 MeV which moves the beam out of the space-charge dominated regime. In the SLAC S-band structures, the RF power feed is through a single coupling-hole (single-feed coupler) which results in a field asymmetry. The time dependent multipole fields in the coupler induce a transverse kick along the bunch and cause the emittance to increase above the LCLS specification. To meet the stringent emittance requirements for the injector, the single-feed couplers will be replaced by a dual-feed racetrack design to minimize the multipole field effects. We will present detailed studies of the multipole fields in the SLAC linac RF coupler and the improvements with the dual-feed ractrack design using the parallel finite element S-parameter solver S3P.
During the past five years, there has been an concerted program at SLAC and KEK to develop accele... more During the past five years, there has been an concerted program at SLAC and KEK to develop accelerator structures that meet the high gradient (65 MV/m) performance requirements for the Next Linear Collider (NLC) and Global Linear Collider (GLC) initiatives. The design that resulted is a 60-cm-long, traveling-wave structure with low group velocity and 150 degree per cell phase advance. It has an average iris size that produces an acceptable short-range wakefield, and dipole mode damping and detuning that adequately suppresses the long-range wakefield. More than eight such structures have operated at a 60 Hz repetition rate over 1000 hours at 65 MV/m with 400 ns long pulses, and have reached breakdown rate levels below the limit for the linear collider. Moreover, the structures are robust in that the rates continue to decrease over time, and if the structures are briefly exposed to air, the rates recover to their low levels within a few days. This paper presents a summary of the results from this program, which effectively ended last August with the selection of ‘cold’ technology for an International Linear Collider (ILC).
Page 1. Revista Fitotecnia Mexicana Sociedad Mexicana de Fitogenética, AC [email protected]... more Page 1. Revista Fitotecnia Mexicana Sociedad Mexicana de Fitogenética, AC [email protected], [email protected] ISSN (Versión impresa): 0187-7380 MÉXICO 2005 Luis Sáenz / Ramón Souza / José Luis Chan ...
Development of micropropagation protocols for Cocos nucifera has progressed slowly. Activated cha... more Development of micropropagation protocols for Cocos nucifera has progressed slowly. Activated charcoal is included in the culture medium of each protocol, mainly to prevent tissue browning. Charcoal production procedures can affect the properties of different brands. In this study, eight types of activated charcoal were evaluated for their effects on free 2,4-dichlorophenoxyacetic acid level, pH, conductivity, and osmolarity of the culture medium and on the frequency of embryogenic callus induction. Moreover, the effect of particle size of the optimum charcoal type on embryogenic callus development was also studied. Charcoal type had a significant effect on (Y3) culture medium properties. Free 2,4-D was highest in Reactivos y Productos Químicos Finos-containing medium and pH was lowest in MERCK-containing medium. Charcoal type also influenced embryogenic callus induction, with acid washed for plant cell and tissue culture-, DARCO- and United States Pharmacopeia-containing media promoting ~60% embryogenic callus, but with different optimal 2,4-D concentrations. Particle size profiles varied among all charcoal types, although small particle fraction (
The increasing demand in México for disease resistant coconut palms (Cocos nucifera L.) requires ... more The increasing demand in México for disease resistant coconut palms (Cocos nucifera L.) requires massive multiplication of improved or selected genotypes. This could be achieved through micropropagation. A reproducible micropropagation protocol via somatic embryogenesis, ...
Tel 01 (917) 375-0396. * Autor responsable RESUMEN El incremento en la demanda de palmas de cocot... more Tel 01 (917) 375-0396. * Autor responsable RESUMEN El incremento en la demanda de palmas de cocotero (Cocos nucifera L.) mejoradas o seleccionadas requiere de su multiplicación masiva. Esto podría ser alcanzado a través de la micropropagación. Existe un protocolo de regeneración reproducible vía embriogénesis somática con explantes de plúmula, pero su eficiencia es todavía baja. Por tanto, el objetivo de este estudio fue evaluar el efecto del ácido abscísico (ABA) y polietilenglicol (PEG) a diferentes concentraciones (0, 22.5, 45 y 90 µM y 0, 15, 30, 60 g L -1 , respectivamente) en la formación de embriones somáticos y su conversión a plantas, a partir de explantes de plúmula de cocotero. La respuesta fue evaluada a los 30, 60, 90, 150 y 210 días después de la adición de ABA o PEG, en el medio II Y3. El mejor tratamiento fue 90 µM de ABA + 15 g L -1 de PEG, que produjo 10.6 embriones somáticos/callo embriogénico a los 150 días y la formación de tres plántulas bien desarrolladas por callo embriogénico a los 210 días. En cambio, los callos embriogénicos testigo solamente formaron 6.2 embriones somáticos y 0.7 plántulas, respectivamente. Las plantas obtenidas con el tratamiento 90 µM ABA + PEG 15 g L -1 y el control fueron aclimatadas y presentaron una supervivencia de 90 % después de un año. Este tratamiento incrementó en 71 % la formación de los embriones somáticos y cuadriplicó la formación de plántulas, lo que mejora la eficiencia total del sistema, que eventualmente podría tener una aplicación práctica. Éste es el primer reporte del efecto de ABA y PEG al utilizar plúmula de cocotero como explante.
in Vitro Cellular & Developmental Biology-plant, 2006
Studies on the development of protocols for the clonal propagation, through somatic embryogenesis... more Studies on the development of protocols for the clonal propagation, through somatic embryogenesis, of coconut have been reported for the past three decades, mostly using inflorescence explants, but with low reproducibility and efficiency. Recent improvements in these respects have been achieved using plumular explants. Here, we report a developmental study of embryogenesis in plumule explants using histological techniques in order to extend our understanding of this process. Coconut plumule explants consisted of the shoot meristem including leaf primordia. At day 15 of culture, the explants did not show any apparent growth; however, a transverse section showed noticeable growth of the plumular leaves forming a ring around the inner leaves and the shoot meristem, which did not show any apparent growth. At day 30, the shoot meristem started to grow and the plumular leaves continued growing., At day 45, the explants were still compact and white in color, but showed partial dedifferentiation and meristematic cell proliferation leading to the development of callus structures with a translucent appearance. After 60 d, these meristematic cells evolved into nodular structures. At day 75, the nodular structures became pearly globular structures on the surface of translucent structures, from which somatic embryos eventually formed and presented well-developed root and caulinar meristems. These results allow better insights and an integrated view into the somatic embryogenesis process in coconut plumule explants, which could be helpful for future studies that eventually could lead us to improved control of the process and greater efficiency of somatic embryo and plantlet formation.
... M. Rubin, N. Newman, JS Chan, TC Fu, and JT Ross Lawrence Berkeley Laboratory, University of ... more ... M. Rubin, N. Newman, JS Chan, TC Fu, and JT Ross Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (Received 28 ... The Ga and Al sources were WA Technologies Series-3 Knudsen cells, and the magnesium source is a Riber Knudsen cell. ...
2011 IEEE International Conference on High Performance Computing and Communications, 2011
Random numbers are used in a wide variety of applications from simulation and encryption to gambl... more Random numbers are used in a wide variety of applications from simulation and encryption to gambling and clinical trials. A good quality random number generator is an asset for applications like encryption, randomized designs and network and information security. Various mathematical models have been developed in the past to improve the quality of random numbers. It can be construed that in general to obtain random numbers of excellent quality, a complex mathematical model has to be used which can be a performance bottleneck. In this work, we propose a novel technique to implement a True Random Number Generator (TRNG) using sources of uncertainty found within Graphics Processing Units (GPUs) together with histogram equalization to obtain maximum entropy. We evaluate the random numbers generated by our approach using four tests. First, we measure the correlation values between two sequences of random numbers, second, we measure the entropy values, third, we use watermarking, an application used in network security and finally we use Monte Carlo analysis for pi-value calculation. Based on these quality measurements, our method has achieved better results than popular random number generators compared in this work. Furthermore, this approach is a massively scalable solution ideal for high performance computing implementations.
2012 IEEE International Conference on Imaging Systems and Techniques Proceedings, 2012
In ultrasound imaging range resolution is proportional to the bandwidth of the transmitted pulse;... more In ultrasound imaging range resolution is proportional to the bandwidth of the transmitted pulse; however, noise also increases with frequency and forces a compromise in imaging accuracy. By compounding multiple synthetic aperture ultrasound images from different frequencies, both the resolution and signal-to-noise ratio (SNR) can be improved, unlike when averaging multiple scans at a single frequency, which would only increase SNR. This paper describes a technique for frequency compounding of synthetic aperture ultrasound images and a practical test setup is introduced for frequency selection for imaging systems consisting of a single piezoelectric transducer and a variable-frequency pulser. An example is provided in which point-scatterers in water are scanned along a linear path at frequencies of 16 to 21 MHz. The resulting multi-frequency imaging increases peak SNR by 13% more than single-frequency averaging with the same number of scans and reduces the rangedomain support of the point-spread function by 30%.
Proceedings of the 2005 Particle Accelerator Conference, 2005
The LCLS injector is required to provide a 1-nC, 10ps bunch with a normalized rms transverse proj... more The LCLS injector is required to provide a 1-nC, 10ps bunch with a normalized rms transverse projected emittance of less than 1 micron. The LCLS beam is generated and accelerated in a 1.6-cell S-band RF gun at 120 MV/m up to 6 MeV. The gun is followed by two SLAC 3-m S-band accelerator structures to further accelerate the beam to 135 MeV which moves the beam out of the space-charge dominated regime. In the SLAC S-band structures, the RF power feed is through a single coupling-hole (single-feed coupler) which results in a field asymmetry. The time dependent multipole fields in the coupler induce a transverse kick along the bunch and cause the emittance to increase above the LCLS specification. To meet the stringent emittance requirements for the injector, the single-feed couplers will be replaced by a dual-feed racetrack design to minimize the multipole field effects. We will present detailed studies of the multipole fields in the SLAC linac RF coupler and the improvements with the dual-feed ractrack design using the parallel finite element S-parameter solver S3P.
Lafarge Corporation has installed several brands of distributed control systems (DCS) and PLC sys... more Lafarge Corporation has installed several brands of distributed control systems (DCS) and PLC systems in our North American plants. In the past, the system selection criteria focused on state-of-the-art technology, plant experience and availability of local services. This paper describes why, with the rapid change of technology today, Lafarge has moved away from such a strategy, and why the AEG Geamatics B system was selected for our plant at Joppa, Illinois. The emergence of the so-called open-platform, and the evolution of classical DCS suppliers to PLC platforms made this decision possible. Implementation and key features of the AEG system at our Joppa plant are described. Also, issues concerning a corporate automation vision and the potential benefits resulting from standardization in a large organization are examined
Designs for a future X-band linear collider (NLC/GLC) require an rf unit that can produce 450 MW ... more Designs for a future X-band linear collider (NLC/GLC) require an rf unit that can produce 450 MW to feed eight 60 cm accelerator structures. The implementation of this rf unit is envisioned to include a dual-moded SLED-II pulse compression system, with a gain of approximately three at a compression ratio of four, followed by an overmoded transmission and distribution system. We describe the tunnel layout plan for these rf systems. The design, construction, and operation of a prototype system are a focus of the 8-Pack project at SLAC. In its initial phase last fall, powered by four 50 MW X-band klystrons sharing a common 400 kV solid-state modulator, the SLED-II system delivered to a set of loads 400 ns pulses of up to 580 MW. In the next phase, this power will be delivered to the NLCTA beamline and distributed between several structures, through which a bunch train will be accelerated. We describe the layout of this system and the functionality of various overmoded, high-power components which comprise it. We also present data on the cold testing, processing and initial operation of the system, which is setting high-power records in pulsed rf.
We have produced 400 ns rf pulses of greater than 500 MW at 11.424 GHz with an rf system designed... more We have produced 400 ns rf pulses of greater than 500 MW at 11.424 GHz with an rf system designed to demonstrate technology capable of powering a TeV scale electron-positron linear collider (NLC). Power is produced by four 50 MW X-band klystrons run off a common 400 kV solid-state modulator. We present the layout of our system, which includes a dual-moded transmission waveguide system and a dual-moded resonant-line (SLED-II) pulse compression system. Dual-moding of the transmission lines allows power to be directed through a pulse compression path or a bypass path; dual-moding in the pulse compressor allows the delay lines to be about half as long as they otherwise would need to be. We describe the design and performance of various components, including hybrids, directional couplers, power dividers, tapers, mode converters, and loads. These components are mostly overmoded to allow for greater power handling. We also present data on the processing and operation of this system, which is setting high-power records in pulsed rf.
Designs for a future TeV scale electron-positron Xband linear collider (NLC/GLC) require main lin... more Designs for a future TeV scale electron-positron Xband linear collider (NLC/GLC) require main linac units which produce and deliver 450 MW of rf power at 11.424 GHz to eight 60 cm accelerator structures. The design of this rf unit includes a SLED-II pulse compression system with a gain of approximately three at a compression ratio of four, followed by an over-moded transmission and distribution system. We have designed, constructed, and operated such a system as part of the 8-Pack project at SLAC. Four 50 MW X-band klystrons, running off a common 400 kV solid-state modulator, drive a dualmoded SLED-II pulse compression system. The compressed power is delivered to structures in the NLCTA beamline. Four 60 cm accelerator structures are currently installed and powered, with four additional structures and associated high power components available for installation late in 2004. We describe the layout of our system and the various high-power components which comprise it. We also present preliminary data on the processing and initial high-power operation of this system.
Physical Review Special Topics - Accelerators and Beams, 2005
We present a multimode X-band rf pulse compression system suitable for a TeV-scale electron-posit... more We present a multimode X-band rf pulse compression system suitable for a TeV-scale electron-positron linear collider such as the Next Linear Collider (NLC). The NLC main linac operating frequency is 11.424 GHz. A single NLC rf unit is required to produce 400 ns pulses with 475 MW of peak power. Each rf unit should power approximately 5 m of accelerator structures. The rf unit design consists of two 75 MW klystrons and a dual-moded resonant-delay-line pulse compression system that produces a flat output pulse. The pulse compression system components are all overmoded, and most components are designed to operate with two modes. This approach allows high-power-handling capability while maintaining a compact, inexpensive system. We detail the design of this system and present experimental cold test results. We describe the design and performance of various components. The high-power testing of the system is verified using four 50 MW solenoid-focused klystrons run off a common 400 kV solidstate modulator. The system has produced 400 ns rf pulses of greater than 500 MW. We present the layout of our system, which includes a dual-moded transmission waveguide system and a dual-moded resonant line (SLED-II) pulse compression system. We also present data on the processing and operation of this system, which has set high-power records in coherent and phase controlled pulsed rf.
The LCLS injector is required to provide a 1-nC, 10-ps bunch with a normalized rms transverse pro... more The LCLS injector is required to provide a 1-nC, 10-ps bunch with a normalized rms transverse projected emittance of less than 1 micron. The LCLS beam is generated and accelerated in a 1.6-cell S-band RF gun at 120 MV/m up to 6 MeV. The gun is followed by two SLAC 3-m S-band accelerator structures to further accelerate the beam to 135 MeV which moves the beam out of the space-charge dominated regime. In the SLAC S-band structures, the RF power feed is through a single coupling-hole (single-feed coupler) which results in a field asymmetry. The time dependent multipole fields in the coupler induce a transverse kick along the bunch and cause the emittance to increase above the LCLS specification. To meet the stringent emittance requirements for the injector, the single-feed couplers will be replaced by a dual-feed racetrack design to minimize the multipole field effects. We will present detailed studies of the multipole fields in the SLAC linac RF coupler and the improvements with the dual-feed ractrack design using the parallel finite element S-parameter solver S3P.
During the past five years, there has been an concerted program at SLAC and KEK to develop accele... more During the past five years, there has been an concerted program at SLAC and KEK to develop accelerator structures that meet the high gradient (65 MV/m) performance requirements for the Next Linear Collider (NLC) and Global Linear Collider (GLC) initiatives. The design that resulted is a 60-cm-long, traveling-wave structure with low group velocity and 150 degree per cell phase advance. It has an average iris size that produces an acceptable short-range wakefield, and dipole mode damping and detuning that adequately suppresses the long-range wakefield. More than eight such structures have operated at a 60 Hz repetition rate over 1000 hours at 65 MV/m with 400 ns long pulses, and have reached breakdown rate levels below the limit for the linear collider. Moreover, the structures are robust in that the rates continue to decrease over time, and if the structures are briefly exposed to air, the rates recover to their low levels within a few days. This paper presents a summary of the results from this program, which effectively ended last August with the selection of ‘cold’ technology for an International Linear Collider (ILC).
Page 1. Revista Fitotecnia Mexicana Sociedad Mexicana de Fitogenética, AC [email protected]... more Page 1. Revista Fitotecnia Mexicana Sociedad Mexicana de Fitogenética, AC [email protected], [email protected] ISSN (Versión impresa): 0187-7380 MÉXICO 2005 Luis Sáenz / Ramón Souza / José Luis Chan ...
Development of micropropagation protocols for Cocos nucifera has progressed slowly. Activated cha... more Development of micropropagation protocols for Cocos nucifera has progressed slowly. Activated charcoal is included in the culture medium of each protocol, mainly to prevent tissue browning. Charcoal production procedures can affect the properties of different brands. In this study, eight types of activated charcoal were evaluated for their effects on free 2,4-dichlorophenoxyacetic acid level, pH, conductivity, and osmolarity of the culture medium and on the frequency of embryogenic callus induction. Moreover, the effect of particle size of the optimum charcoal type on embryogenic callus development was also studied. Charcoal type had a significant effect on (Y3) culture medium properties. Free 2,4-D was highest in Reactivos y Productos Químicos Finos-containing medium and pH was lowest in MERCK-containing medium. Charcoal type also influenced embryogenic callus induction, with acid washed for plant cell and tissue culture-, DARCO- and United States Pharmacopeia-containing media promoting ~60% embryogenic callus, but with different optimal 2,4-D concentrations. Particle size profiles varied among all charcoal types, although small particle fraction (
The increasing demand in México for disease resistant coconut palms (Cocos nucifera L.) requires ... more The increasing demand in México for disease resistant coconut palms (Cocos nucifera L.) requires massive multiplication of improved or selected genotypes. This could be achieved through micropropagation. A reproducible micropropagation protocol via somatic embryogenesis, ...
Tel 01 (917) 375-0396. * Autor responsable RESUMEN El incremento en la demanda de palmas de cocot... more Tel 01 (917) 375-0396. * Autor responsable RESUMEN El incremento en la demanda de palmas de cocotero (Cocos nucifera L.) mejoradas o seleccionadas requiere de su multiplicación masiva. Esto podría ser alcanzado a través de la micropropagación. Existe un protocolo de regeneración reproducible vía embriogénesis somática con explantes de plúmula, pero su eficiencia es todavía baja. Por tanto, el objetivo de este estudio fue evaluar el efecto del ácido abscísico (ABA) y polietilenglicol (PEG) a diferentes concentraciones (0, 22.5, 45 y 90 µM y 0, 15, 30, 60 g L -1 , respectivamente) en la formación de embriones somáticos y su conversión a plantas, a partir de explantes de plúmula de cocotero. La respuesta fue evaluada a los 30, 60, 90, 150 y 210 días después de la adición de ABA o PEG, en el medio II Y3. El mejor tratamiento fue 90 µM de ABA + 15 g L -1 de PEG, que produjo 10.6 embriones somáticos/callo embriogénico a los 150 días y la formación de tres plántulas bien desarrolladas por callo embriogénico a los 210 días. En cambio, los callos embriogénicos testigo solamente formaron 6.2 embriones somáticos y 0.7 plántulas, respectivamente. Las plantas obtenidas con el tratamiento 90 µM ABA + PEG 15 g L -1 y el control fueron aclimatadas y presentaron una supervivencia de 90 % después de un año. Este tratamiento incrementó en 71 % la formación de los embriones somáticos y cuadriplicó la formación de plántulas, lo que mejora la eficiencia total del sistema, que eventualmente podría tener una aplicación práctica. Éste es el primer reporte del efecto de ABA y PEG al utilizar plúmula de cocotero como explante.
in Vitro Cellular & Developmental Biology-plant, 2006
Studies on the development of protocols for the clonal propagation, through somatic embryogenesis... more Studies on the development of protocols for the clonal propagation, through somatic embryogenesis, of coconut have been reported for the past three decades, mostly using inflorescence explants, but with low reproducibility and efficiency. Recent improvements in these respects have been achieved using plumular explants. Here, we report a developmental study of embryogenesis in plumule explants using histological techniques in order to extend our understanding of this process. Coconut plumule explants consisted of the shoot meristem including leaf primordia. At day 15 of culture, the explants did not show any apparent growth; however, a transverse section showed noticeable growth of the plumular leaves forming a ring around the inner leaves and the shoot meristem, which did not show any apparent growth. At day 30, the shoot meristem started to grow and the plumular leaves continued growing., At day 45, the explants were still compact and white in color, but showed partial dedifferentiation and meristematic cell proliferation leading to the development of callus structures with a translucent appearance. After 60 d, these meristematic cells evolved into nodular structures. At day 75, the nodular structures became pearly globular structures on the surface of translucent structures, from which somatic embryos eventually formed and presented well-developed root and caulinar meristems. These results allow better insights and an integrated view into the somatic embryogenesis process in coconut plumule explants, which could be helpful for future studies that eventually could lead us to improved control of the process and greater efficiency of somatic embryo and plantlet formation.
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Papers by Jose Chan