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Using high-throughput data and dynamic flux balance modeling techniques to identify points of constraint in xylose utilization in Saccharomyces cerevisiae

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Systems Microbiology and Biomanufacturing 2021年第1期1卷 58-75页

作者： William Hohenschuh ronald E.hector Frank Chaplen Ganti S.Murthy Oregon State University CorvallisUSA USDA ARSNCAURPeoriaUSA Present Address:EMD Serono Inc. RocklandUSA Present Address:Indian Institute of Technology-Indore IndoreIndia

Background Several enzymes and cofactors have been identified as contributing to the slow utilization of xylose by xylose-fermenting strains of Saccharomyces ***,there has been no consensus on which of these possible bottle-necks are the most important to address.A previous strain characterization study from our lab suggested that insufficient NAD+limits fermentation and may be the most important bottleneck affecting utilization of xylose for the production of *** development and validation of a genome scale dynamic flux balance model would help to verify the existence and extent of this and other metabolic bottlenecks and suggest solutions to guide future strain development thereby minimiz-ing bottleneck impact on process *** A dynamic flux balance model was developed to identify bottlenecks in several strains of ***,both with wild-type pentose phosphate pathway expression and with the pathway over ***1 was found to be limiting in the oxidative portion of the pentose phosphate pathway under oxygen replete *** pathway is used to regenerate *** oxygen limiting conditions,respiration of xylose was limited by the lack of oxygen as a terminal electron *** production was also limited under these conditions due to the inability to balance NAD+/*** model suggests the use of the anaplerotic glyoxylate pathway to improve NAD+/NADH balance,increasing ethanol produc-tion by 50%while producing succinate as a coproduct at upwards of 20 g/*** In the production of high value chemicals from biomass,the use of the respiratory metabolism is a waste of feedstock *** previously identified in the oxidative pentose phosphate pathway are currently only relevant under oxygen-replete conditions and cannot impact the partitioning of carbon between the respiratory and fermentative *** future efforts on the non-respiratory balancing of NAD+/NADH,perhaps through th

关键词： Xylose Ethanol Biofuel Lignocellulose Metabolic bottlenecks Flux balance analysis Modeling Cofactor imbalance Glyoxylate pathway NAD+ NADH

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From Bench to the Clinic: The Path to Translation of Nanotechnology-Enabled mrNA SArS-CoV-2 Vaccines

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Nano-Micro Letters 2022年第3期14卷 1-31页

作者： Diana O.Lopez‑Cantu Xichi Wang hector Carrasco‑Magallanes Samson Afewerki Xingcai Zhang Joseph V.Bonventre Guillermo U.ruiz‑Esparza Division of Engineering in Medicine Department of MedicineBrigham and Women’s HospitalHarvard Medical SchoolBostonMA 02115USA Division of Health Sciences and Technology Harvard University-Massachusetts Institute of TechnologyBostonMA 02115USA Division of renal Medicine Department of MedicineBrigham and Women’s HospitalHarvard Medical SchoolBostonMA 02115USA Tecnologico de Monterrey School of Engineering and Sciences64849 MonterreyNLMexico Department of Cardiovascular Surgery Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430022People’s Republic of China Harvard T.H.Chan School of Public Health BostonMA 02115USA Tecnologico de Monterrey School of Medicine and Health Sciences64849 MonterreyNLMexico John A.Paulson School of Engineering and Applied Sciences Harvard UniversityCambridgeMA 02138USA School of Engineering Massachusetts Institute of TechnologyCambridgeMA 02139USA

During the last decades,the use of nanotechnology in med icine has effectively been translated to the design of drug delivery systems,nanostructured tissues,diagnostic platforms,and novel nanomaterials against several human diseases and infectious ***-enabled vaccines have been positioned as solutions to mitigate the pandemic outbreak caused by the novel pathogen severe acute respiratory syndrome coronavirus *** fast-track the development of vaccines,unprecedented industrial and academic collaborations emerged around the world,resulting in the clinical translation of effective vaccines in less than one *** this article,we provide an overview of the path to translation from the bench to the clinic of nanotechnology-enabled messenger ribonucleic acid vaccines and examine in detail the types of delivery systems used,their mechanisms of action,obtained results during each phase of their clinical development and their regulatory approval *** also analyze how nanotechnology is impacting global health and economy during the COVID-19 pandemic and beyond.

关键词： Nanovaccines mrNA Coronavirus SArS-CoV-2 COVID-19

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High pressure responsive luminescence of flexible Eu^(3+) doped PVDF fibrous mats

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Journal of Materials Science & Technology 2021年第7期66卷 103-111页

作者： Carlos Hernandez San tosh K.Gupta Jose P.Zuniga Jorge Vidal rene Galvan hector Guzman Lilian Chavez Karen Lozano Yuanbing Mao Department Department of Chemistry University of Texas Rio Grande Valley1201 West University DriveEdinburgTX 78539USA radiochemistry Division Bhabha Atomic Research CentreTrombayMumbai400085USA Department of Electrical Engineering University of Texas Rio Grande ValleyEdinburgTX 78539USA Department of Chemistry Illinois Institute of Technology3105 South Dearborn StreetChicagoIL 60616USA

Exploring lanthanide doped materials and their high-pressure optical properties is important from the perspective of designing pressure sensors, piezoelectric materials, scintillators, and optoelectronic devices, just to mention a few. Understanding the high-pressure optical properties of polymeric fibrous mats provides significant advantages in terms of flexibility, tunability, facile processability, and malleability. In this work, we have developed flexible polyvinylidene difluoride(PVDF) fibrous mats doped with an Eu^(3+) source of Eu(NO_(3))_(3)·5H_(2)O(EN-PF) or Eu_(2)(SO_(4))_(3)(ES-PF) by a Forcespinning■ method. Microstructural analysis of these two systems indicates that Eu(NO_(3))_(3)·5H_(2)O and Eu_(2)(SO_(4))_(3) are homogeneously distributed and dispersed into the PVDF matrix. Fiber formation promotes a β-phase PVDF. Eu^(3+) doping increases the β-phase. Its fraction is larger for the ES-PF mats. To understand their high-pressure optical properties, their photoluminescence spectra have been taken at various pressures up to 58 GPa in a diamond anvil cell. High-pressure luminescence illustrates a clear change in asymmetry ratio, peak intensity, peak breadth, color coordinate, and color temperature of Eu^(3+) ions from both EN-PF and ES-PF with a different extent of changes. Specifically, Eu^(3+) ions in the ES-PF mats switch from asymmetric to symmetric environment as pressure increases. Those in the EN-PF mats present symmetric environment for all tested pressures. Both of the Eu^(3+) doped PVDF systems present irreversible changes. Therefore,the EN-PF fibrous mats present an opportunity to make pressure induced red-orange-yellow tunable phosphors for multifunctional applications.

关键词： Polyvinylidene difluoride Europium Fiber High pressure Luminescence

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遗传性短QT综合征的研究进展

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中华心血管病杂志 2019年第5期47卷 413-416页

作者：石少波 hector Barajas-Martinez 胡丹武汉大学人民医院心内科武汉大学心血管病研究所心血管病湖北省重点实验室 430060 美国宾夕法尼亚州温纽伍德市兰肯瑙医学研究所 19096

短QT综合征是以QT间期缩短、心脏性猝死高风险为特征的遗传性心脏离子通道病。它属于常染色体显性遗传,发病罕见,与编码钾通道和钙通道的基因突变有关,基因突变导致的IKr、IKs、IK1增大和ICa,L功能丢失,使净外向电流增加或内向电流减少... 详细信息

短QT综合征是以QT间期缩短、心脏性猝死高风险为特征的遗传性心脏离子通道病。它属于常染色体显性遗传,发病罕见,与编码钾通道和钙通道的基因突变有关,基因突变导致的IKr、IKs、IK1增大和ICa,L功能丢失,使净外向电流增加或内向电流减少,复极加速,动作电位时程缩短和复极离散度增加,最终触发室性心动过速/心室颤动(VT/VF)。植入式心脏复律除颤器是唯一有效的防治心脏性猝死的手段,奎尼丁和索他洛尔通过延长有效不应期和QT间期,可有效预防VT/VF。

关键词：短QT综合征心脏性猝死流行病学

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Lower marine productivity increases agonistic interactions between sea lions and fur seals in Northern Pacific Patagonia

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Current Zoology 2022年第6期68卷 657-666页

作者： Felipe MONTALVA hector PAVES Diego PErEZ-VENEGAS Karin G BArrIENTOS E Carola VALENCIA Diego MIrANDA-UrBINA Mauricio SEGUEL Facultad de Ciencias Biologicas Pontificia Universidad Catolica de ChileSantiagoChile Departamento de Ciencias Basicas Facultad de CienciasUniversidad Santo TomasOsornoChile Centro de Investigacion y Gestion de recursos Naturales(CIGrEN) Instituto de BiologıaFacultad de CienciasUniversidad de ValparaısoValparaısoChile Programa de Doctorado en Ciencias Agrarias Escuela de Graduados de laFacultad de Ciencias Agrarias y AlimentariasUniversidad Austral de ChileValdiviaChile Facultad de Medicina Veterinaria Sede PatagoniaUniversidad San SebastianPuerto MonttChile Instituto de Ciencias Biologicas Universidad de TalcaTalcaChile Department of Pathobiology Ontario Veterinary CollegeUniversity of GuelphGuelphCanada

Interspecific interactions are key drivers of individual and population-level fitness in a wide range of ***,in marine ecosystems,it is relatively unknown which biotic and abiotic factors impact behavioral interactions between competing *** assessed the impact of weather,marine productivity,and population structure on the behavioral agonistic interactions between South American fur seals(SAFSs),Arctocephalus australis,and South American sea lions(SASLs),Otaria byronia,in a breeding colony of *** hypothesized that agonistic interactions between SAFSs and SASLs respond to biotic and abiotic factors such as SAFS population structure,marine productivity,and *** found that SASL and SAFS interactions almost always resulted in negative impacts on the social structure or reproductive success of the SAFS *** adult males initiated stampedes of SAFS and/or abducted and predated SAFS *** SAFS males abundance and severe weather events were negatively correlated with agonistic interactions between ***,proxies for lower marine productivity such as higher sea surface temperature and lower catches of demerso-pelagic fish were the most important predictors of more frequent agonistic interactions between SAFS and *** the current scenario of decline in marine biomass due to global climate change and overfishing,agonistic interactions between competing marine predators could increase and exacerbate the negative impacts of environmental change in these species.

关键词： interspecific interactions climate change Guafo Island sea surface temperature South American fur seal South American sea lion

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Scalable and automated CrISPr-based strain engineering using droplet microfluidics

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Microsystems & Nanoengineering 2022年第2期8卷 227-236页

作者： Kosuke Iwai Maren Wehrs Megan Garber Jess Sustarich Lauren Washburn Zachary Costello Peter W.Kim David Ando William r.Gaillard Nathan J.Hillson Paul D.Adams Aindrila Mukhopadhyay hector Garcia Martin Anup K.Singh Technology Division DOE Joint BioEnergy InstituteEmeryvilleCA 94608USA Biotechnology and Bioengineering Department Sandia National LaboratoriesLivermoreCA 94550USA Biofuels and Bioproducts Division DOE Joint BioEnergy InstituteEmeryvilleCA 94608USA Biological Systems and Engineering Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Molecular Biophysics and Integrated Bioimaging Division Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Department of Bioengineering University of CaliforniaBerkeleyCA 94720USA BCAM Basque Center for Applied MathematicsBilbao 48009Spain

We present a droplet-based microfluidic system that enables CrISPr-based gene editing and high-throughput screening on a *** microfluidic device contains a 10x10 element array,and each element contains sets of electrodes for two electric field-actuated operations:electrowetting for merging droplets to mix reagents and electroporation for *** device can perform up to 100 genetic modification reactions in parallel,providing a scalable platform for generating the large number of engineered strains required for the combinatorial optimization of genetic pathways and predictable *** demonstrate the system's capabilities through the CrISPr-based engineering of two test cases:(1)disruption of the function of the enzyme galactokinase(galK)in£coli and(2)targeted engineering of the glutamine synthetase gene(glnA)and the blue-pigment synthetase gene(bpsA)to improve indigoidine production in£coli.

关键词： operations generating fluid

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Improving the reliability of Unmanned Aircraft System Wireless Communications through Cognitive radio Technology

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Communications and Network 2013年第3期5卷 225-230页

作者： hector reyes Naima Kaabouch Electrical Engineering Department University of North Dakota Grand Forks USA

Unmanned Aircraft System networks are a special type of networks where high speeds of the nodes, long distances and radio spectrum scarcity pose a number of challenges. In these networks, the strength of the transmitted/received signals varies due to jamming, multipath propagation, and the changing distance among nodes. High speeds cause another problem, Doppler Effect, which produces a shifting of the central frequency of the signal at the receiver. In this paper we discuss a modular system based on cognitive to enhance the reliability of UAS networks.

关键词： UAS Intelligent Communication Systems Cognitive radio reliability

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Where do random rough Surfaces Fail？ Part I： Fracture Loci Safety Envelopes at Early Stages of Degradation

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Journal of Energy and Power Engineering 2013年第5期7卷 907-916页

作者： hector Medina Brian Hinderliter Virginia Commonwealth University Richmond VA 23284-3015 USA

Damage on surfaces often compromises the efficiency of some types of energy production, the safety and reliability of components, and ultimately increases costs. The environment can degrade the structural integrity of surfaces in service by the accumulation of large numbers of small destructive events, which based on the Central Limit Theorem leads to a Gaussian distribution of pit depth. In order to develop safety envelopes relating fracture loci with topological parameters of a brittle material, scatter plots were obtained and analyzed. Starting with an engineering surface, after 6 to 9 micrometers of average degradation depth, safety envelopes could be developed using average roughness and two other proposed parameters. Interestingly, maximum pit depth showed very low correlation with the location of fracture, at the early stage of degradation studied. This is attributed to relaxation of stress concentration at a given pit location due to the assuaging effect caused by neighboring pits. Additionally, energy at fracture was obtained, and a maximum relaxation region was observed. Analytical and experimental study of this region, as well as ductility effects are currently under research.

关键词： Safety envelopes roughness surfaces.

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Evaluating soil erosion and runoff dynamics in a humid subtropic, low stream order, southern plains watershed from cultivation and solar farm development

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International Soil and Water Conservation research 2024年第2期12卷 432-445页

作者： Luis Mier-Valderrama Julianna Leal Humberto L.Perotto-Baldivieso Brent Hedquist hector M.Menendez Ambrose Anoruo Benjamin L.Turner Department of Agriculture Agribusinessand Environmental ScienceTexas A&M University-KingsvilleKingsvilleTXUSA Department of rangeland and Wildlife Sciences And Caesar Kleberg Wildlife Research InstituteTexas A&M University-KingsvilleKingsvilleTXUSA Department of Physics and Geosciences Texas A&M University-KingsvilleKingsvilleTXUSA South Dakota State University West River Ag CenterRapid CitySDUSA

Much work has been done to understand and improve soil and water conservation where agriculture has driven land use *** is known about soil-and water-related impacts from intensification driven by solar farming,especially at *** we employed Hydrologic Engineering Center's Hydrologic Modeling System(HEC-HMS)to model Pond Creek,a rural watershed in Texas,*** use is primarily crop cultivation and secondarily pasture for cattle ***,several industrial-scale projects are planned to convert≈15–30%of Pond Creek from agriculture to solar *** model was parameterized using public data sources and information from local stakeholders,then calibrated to several historical precipitation *** were conducted by varying precipitation depth,duration,and land uses:native vegetation pre-cultivation(control),cultivation(current),current conditions with 15%solar farm conversion(solar),and current conditions with 30%solar farm conversion(solar x2).Shifting to solar farming led to significant increases in cumulative sediment load(+12%–30%),with no significant differences in peak discharge rate changes(+0.38%–4%).Comparison to soil loss tolerance values showed current and solar treatment erosion rates exceeded tolerance values between 0.17 and 2.29 tons per hectare and all treatments were significantly different than the native *** discuss high leverage strategies applicable to solar farm development sites as well as watersheds where they *** demand for land for renewable energy such as solar farming warrants greater attention from the soil and water conservation community to anticipate and mitigate impacts across landscapes.

关键词： Erosion Sediment loading runoff Watershed management Solar energy HEC-HMS

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Development and characterization of Saccharomyces cerevisiae strains genetically modified to over-express the pentose phosphate pathway regulating transcription factor STB5 in the presence of xylose

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Systems Microbiology and Biomanufacturing 2021年第1期1卷 42-57页

作者： William Hohenschuh ronald E.hector Jeffrey A.Mertens Ganti S.Murthy Biological and Ecological Engineering Oregon State University116 Gilmore HallCorvallisOR 97331USA USDA ARSNCAURPeoriaIL 61604USA Present Address:EMD Serono Inc. RocklandMA 02370USA Present Address:Biosciences and Biomedical Engineering Indian Institute of Technology-IndorePOD 1A704 Khandwa RoadSimrolMadhya Pradesh 453552India

Background Several enzymes in the pentose phosphate pathway of Saccharomyces cerevisiae have been identified as relating to the constraint of xylose consumption and conversion to ***,no strategy has been proposed for simultaneous regulation of all contributing *** multiple enzymes contribute to constraint,over expression of a native transcription factor controlling the entire constraining pathway may provide optimal pathway wide *** characterization of this strain on both pure sugars and lignocellulosic hydrolysates would provide an opportunity to identify additional bot-tlenecks not addressed by the modification of the pentose phosphate pathway expression *** A series of strains were developed expressing STB5 and PGI1 under the control of a novel xylose inducible *** transcription of STB5 and its regulatory targets was verified via *** statistically significant difference was found in terms of xylose consumption or ethanol yield in these strains versus control *** consumption through both the fermentative and respiratory pathways appeared to be related to oxygen availability and culture density with high-density(low oxygen)cultures consuming xylose more slowly than low-density *** maximum specific consumption rate for high-density cultures was 0.21 g xylose/gDCW/h versus 0.41 g xylose/gDCW/h in lower density *** similar ethanol yields at high and low density(approximately 0.25 g ethanol/g xylose)suggest that the maximum rate of fermentation is linked to the rate of respiration in a stoichiometric *** This study did not find evidence supporting the pentose phosphate pathway constraint identified in other ***,NAD+availability mediated by oxygen availability and citric acid cycle flux was suggested to limit *** increased aeration could provide increased conversion of NAD+to NADH(and a stoichiometric increase in fermen-tatio

关键词： Xylose Ethanol Biofuel Lignocellulose Metabolic bottlenecks STB5 Xylose inducible NAD+/NADH Cofactor imbalance Saccharomyces cerevisiae

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