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Mechanical Shaking and Baling of Balsam Fir Trees Influence Postharvest Needle Senescence and Abscission

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American Journal of Plant Sciences 2018年第3期9卷 339-352页

作者： Ernest A. Korankye rajasekaran r. Lada Samuel K. Asiedu Claude Caldwell Department of Plant Food and Environmental Sciences Faculty of Agriculture Dalhousie University Halifax NS Canada

This study investigated the influence of both shaking duration and number of trees per bale on postharvest needle characteristics such as percentage needle loss, needle retention duration and explored the physiological roles of endogenous ethylene and volatile terpene compounds (VTCs). To accomplish these objectives, 25 six-year-old trees were detached and exposed to a range of shaking durations (0 to 60 sec.), and 30 six-year-old detached trees were exposed to baling treatments from 0 to 5 trees. response variables measured were percent needle loss, needle retention duration, average water use, ethylene and volatile terpene compound evolution. Trees shaken for 60 seconds lost 16% less needle compared to control, which was consistent with the decrease in percent needle loss with increasing shaking duration. Baled trees lost 13% more needles compared to control, but percent needle loss was observed to decrease with increasing number of trees in a bale. These trends corresponded with increasing ethylene and VTC evolutions, where the longer the shaking duration or larger number of trees in a bale, the higher the ethylene and VTC evolutions. One can therefore draw inference that mechanical perturbation as a result of shaking and baling induce biosynthesis and regulation of ethylene and VTC in balsam fir trees in an effort to regulate postharvest needle abscission.

关键词： Shaking Baling Ethylene Volatile Terpene Compounds Needle Loss Thigmomorphogenesis

Qualitative Assessment of Postharvest Stomata and Chloroplast Degradation in Contrasting Abscission resistant Balsam Fir (Abies balsamea (L.) Mill.)

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American Journal of Plant Sciences 2023年第9期14卷 1009-1028页

作者： Gaye MacDonald rajasekaran r. Lada C. D. Caldwell Chibuike C. Udenigwe Mason T. Maconald Faculty of Agriculture Dalhousie University Bible Hill Canada School of Nutritional Sciences Faculty of Health Sciences University of Ottawa Ottawa Canada

Balsam fir is an important Christmas tree species, especially in eastern Canada. The natural Christmas tree industry faces a challenge in postharvest needle abscission. Though there have been many studies describing the physiological triggers and consequences in postharvest balsam fir, there have been no studies describing morphological or ultrastructural changes. Therefore, the objective of this study was to examine changes in stomata and chloroplast of postharvest needles. Branches were collected from low and high needle abscission resistance balsam fir genotypes, placed in water, and displayed in typical household conditions for 11 weeks. Needle abscission, chlorophyll fluorescence, and water uptake were monitored throughout. Needles stomata and chloroplasts were examined under a scanning and transmission electron microscope, respectively, each week. All branches had increased abscission, decreased chlorophyll fluorescence, and decreased water uptake over time. Needle surfaces accumulated fungal hyphae, especially in stomata. Chloroplasts demonstrated some dysfunction within two weeks, with notable decreases in chloroplast starch and increases in plastoglobulins. Within several weeks thylakoid membranes had been dismantled as chloroplasts transformed into gerontoplasts. All biophysical and structural changes were more pronounced in low needle abscission resistant genotypes. This research identifies a potential role for needle fungi in postharvest needle abscission and confirms the postharvest senescence of chloroplasts. Though it was previously speculated that chloroplasts must senesce postharvest, this study identifies how quickly this process occurs and that it occurs at different rates in contrasting genotypes.

关键词： Abies balsamea Balsam Fir Christmas Tree Fluorescence Needle Abscission resistance Scanning Electron Transmission Electron

Potential roles of Fatty Acids and Lipids in Postharvest Needle Abscission Physiology

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American Journal of Plant Sciences 2019年第6期10卷 1069-1089页

作者： Gaye E. MacDonald rajasekaran r. Lada Claude D. Caldwell Chibuike Udenigwe Mason T. MacDonald Department of Plant Food and Environmental Sciences Faculty of Agriculture Dalhousie University Halifax Canada School of Nutrition Sciences Faculty of Health Sciences University of Ottawa Ottawa Canada

Our understanding of postharvest needle abscission physiology in conifers has greatly improved in the last decade. Abscission is initially triggered by root detachment, which begins a cascade of changes such as decreased water uptake, water potential, and auxins and increased membrane injury, ethylene, abscisic acid, volatile terpenes, and catalytic enzymes. Needle abscission is also affected by environmental factors. For example, a period of cold acclimation generally delays postharvest abscission. The aforementioned pieces of evidence, along with previous studies, strongly points to a role for plant lipids and fatty acids. Studies from other species have pointed out key roles in abscission and stress responses for a variety of phospholipids and galactolipids, which has not been studied in balsam fir. It is imperative to have an understanding of the role of plant lipids and fatty acids to further our overall understanding of the physiological mechanisms of postharvest abscission and needle abscission resistance. This review is an overview of membrane lipids and fatty acids, changes that occur postharvest and the interaction that lipids may have in the phenomenon of postharvest abscission.

关键词： Phospholipids Galactolipids Fatty Acids Plant Growth regulators Abscission

Coarse to Fine: The role of Severe Plastic Deformation in Advancing Titanium-Based Medical Implants - A Comprehensive review

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 295-306页

作者： Dragana r Mihajlović Bojan I Međo Ivana Lj Cvijović-Alagić Veljko r Djokić Faculty of Technology and Metallurgy University of BelgradeKarnegijeva 411120 BelgradeSerbia Vinča Institute of Nuclear Sci-ences-National Institute of the republic of Serbia University of Belgrade11001BeogradSerbia Innovation Centre of the Faculty of Technology and Metallurgy Karnegijeva 411120 BelgradeSerbia

This paper describes severe plastic deformation(SPD)procedures,which are utilized to form an ultrafine-grained structure in metallic *** the SPD process,a solid material sample is subjected to very high loads without a significant change in sample *** the present work,the high-pressure torsion(HPT)process,as one of the SPD techniques,which achieves a high degree of deformation and ensures refinement of the microstructure,will be discussed in more *** that grain size control is accepted as a method to obtain materials with desired characteristics,an overview of the properties of ultrafine-grained titanium-based biomaterials to be used in medicine is ***,particular attention is dedicated to the influences of HPT process parameters,primarily hydrostatic pressure,and number of revolutions during torsion,on the grain size and physical and mechanical characteristics(modulus of elasticity,microhardness,and tensile properties),corrosion resistance,and biocompatibility of the titanium-based biomaterials.A review of the literature indicates that titanium-based materials obtained by the SPD process show improved mechanical and physical properties without losing biocompatibility and corrosion resistance,which suggests that these methods of obtaining implants are something that should be further developed in the future.

关键词： high-pressure torsion process ultrafine-grained titanium-based materials electrochemical anodization physical properties mechanical properties

Emerging potential of progranulin-dependent SorCS2 signaling in healthy and diseased nervous systems

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Neural regeneration research 2025年第9期20卷 2591-2593页

作者： Alena Salasova Anders Nykjær Danish research Institute of Translational Neuroscience DANDrITE-Nordic EMBL Partnership for Molecular Medicine and Centre of Excellence PROMEMODepartment of BiomedicineAarhus UniversityAarhusDenmark

The formation of the mammalian nervous system and its maturation into sensory,motor,cognitive,and behavioral circuits is a complex process that begins during early embryogenesis and lasts until young *** neurodevelopm... 详细信息

关键词： progr jointly CS2

Performance Analysis of a Heterogeneous Network Employing DAPSK Based OFDMA-PON

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China Communications 2023年第3期20卷 128-145页

作者： Priyadharshini rajasekaran Geetha Ganesan Department of Electronics and Communication Engineering Sri Venkateswara College of EngineeringSriperumbudur 602117Tamil NaduIndia Department of Electronics and Communication Engineering College of Engineering GuindyAnna UniversityChennai 600025Tamil NaduIndia

recent mobile broadband networks require heterogeneous networks supporting high capacity on demand.A hybrid Fiber-Wireless(Fi-Wi)access network integrating Differential Amplitude and Phase Shift Keying(DAPSK)based-Orthogonal Frequency Division Multiple Access(OFDMA)Passive Optical Network(PON)and 4G wireless network using radio over Fiber(ro F)technique is *** proposed heterogeneous network is simulated,and the performance is analyzed in terms of Bit Error rate(BEr),Error Vector Magnitude(EVM),Capacity,and Spectral *** proposed network is simulated considering a higher data rate of 10 and 25 Gbps,and the effect of system parameters like Laser Power,Fiber Length,and Number of users is *** results show that a higher network capacity of 720 Gbps with an average capacity of about 45 Gbps and a higher spectral efficiency of 4.85 bps/Hz is achieved for the multi-user heterogeneous network link with sixteen *** minimum value of optical power sufficient to achieve the desired BEr is found to be-6 *** suitability of the proposed integrated architecture in supporting multiple services is analyzed by considering different services at each *** spectral efficiency of the multi-service link varies from 3 to 4 bps/Hz.

关键词： DAPSK OFDMA PON roF Spectral ef-ficiency

Security Strategy of Digital Medical Contents Based on Blockchain in Generative AI Model

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Computers, Materials & Continua 2025年第1期82卷 259-278页

作者： Hoon Ko Marek r.Ogiela Division of Computer Science and Engineering Sunmoon UniversityAsan31460Republic of Korea AGH University of Krakow Cryptography and Cognitive Informatics LaboratoryKrakow30-059Poland

This study presents an innovative approach to enhancing the security of visual medical data in the generative AI environment through the integration of blockchain *** combining the strengths of blockchain and generative AI,the research team aimed to address the timely challenge of safeguarding visual medical *** participating researchers conducted a comprehensive analysis,examining the vulnerabilities of medical AI services,personal information protection issues,and overall security *** multi faceted exploration led to an indepth evaluation of the model’s performance and ***,the correlation between accuracy,detection rate,and error rate was *** analysis revealed insights into the model’s strengths and limitations,while the consideration of standard deviation shed light on the model’s stability and performance *** study proposed practical improvements,emphasizing the reduction of false negatives to enhance detection rate and leveraging blockchain technology to ensure visual data integrity in medical *** blockchain to generative AI-created medical content addresses key personal information protection *** utilizing the distributed ledger system of blockchain,the research team aimed to protect the privacy and integrity of medical data especially medical *** approach not only enhances security but also enables transparent and tamperproof ***,the use of generative AI models ensures the creation of novel medical content without compromising personal information,further safeguarding patient *** conclusion,this study showcases the potential of blockchain-based solutions in the medical field,particularly in securing sensitive medical data and protecting patient *** proposed approach,combining blockchain and generative AI,offers a promising direction toward more robust and secure medical content *** research and advancements

关键词： Digitalmedical content medical diagnostic visualization security analysis generativeAI blockchain vulnerability pattern recognition

Distribution of persistent organic pollutants in aggregate fractions of a temperate forest and semi-rural soil

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Journal of Forestry research 2017年第5期28卷 953-962页

作者： Shafique Maqsood rajasekaran Murugan Department of Environmental Chemistry University of Kassel Department of Physical Geography Georg August-University Goettingen Department of Soil Biology and Plant Nutrition University of Kassel

The fate of persistent organic pollutants (POPs) and their interactions with aggregates of forest soils are not completely understood. Our objectives here were to quantify the distribution of different POPs in water-stable aggregate fractions and to study their influence on soil organic carbon (Corg) content. Soil samples were taken from a forest-site, Gogerddan (G) and a semi-rural site, Hazelrigg (H) in Great Britain, from 0-2 and 2-5 cm and 0-4 and 8-12 cm soil depth, respectively. POPs analyzed were PAHs, PCBs, total DDT, PBDEs and HCB. The bulk soil analysis showed that the concentration of POPs was significantly higher (p ≤ 0.05) in forest site G than in semi-rural site H, particularly at the surface soil levels compared to the subsurface soil depths in both sites. Total concentrations of PCBs and PAHs of both sites were positively correlated with Corg contents. POPs concentrations and Corg, Nt contents of forest site G were significantly higher (p ≤ 0.05) in water-stable macro aggregates (>0.25, >1, >2 mm) than the micro aggregates (>0.053 mm). The POP concentrations of all aggregate fractions after normalizing to their respective Corg content were increased due higher contamination and strong sorption by Corg. These results showed a strong effect of Corg on the partitioning of organic pollutants to soil aggregate size fractions. The present study affirms the ecological significance of forest soils act as a potential sink of POPs. In summary, our results suggest that aggregate fractions may promote soil C storage and act as a potential POP sink in surface soil without increasing their concentration in the aggregate fraction of subsoil.

关键词： Aggregate fractions Forest soil Organic carbon Persistent organic pollutants

Mapping of hard rock aquifer system and artificial recharge zonation through remote sensing and GIS approach in parts of Perambalur District of Tamil Nadu, India

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Journal of Groundwater Science and Engineering 2019年第3期7卷 264-281页

作者： A Muthamilselvan N rajasekaran r Suresh Dept.of.remote Sensing Bharathidasan UniversityTiruchirappalliIndia Dept.of Geology Periyar UniversitySalemIndia

Mapping of hard rock aquifer system and artificial recharge zonation were carried out in an area of 325 km^2 in parts of the Perambalur District,Tamil Nadu,*** district has been declared as one of the over-exploited regions in Tamil Nadu by the Central Groundwater *** raise the groundwater level,suitable recharge zones were identified and artificial recharge structures are suggested using geomatics technology in the present *** this end,various thematic maps concerning lithology,soil,geomorphology,land use,land cover,slope,lineament,lineament density,drainage,drainage density and groundwater depth level were *** hornblende gneiss(244 km^2)covered most of the study area followed by charnockites(68 km^2).Structural hills and rocky pediments characterize the major geomorphological features in the targeted area,and are followed by deep moderated *** area is mostly used as crop and fallow land,followed by scrub land and deciduous *** the study area,the slopes are predominantly very gentle(142 km^2)and nearly level(66 km^2)***,Groundwater level data of 58 wells have been generated,in which the minimum and maximum depth were 3 and 28 m *** under the GIS environment has been carried out using all the thematic layers to identify the groundwater prospect zone through the introduction of weight and rank *** output performances were classified into very poor,poor,moderate,good and excellent *** these classes were further divided into two groups as suitable and non-suitable area for the selection of recharge *** rock fractures were mapped as lineaments from satellite images,and besides that,rose diagram was also generated to find out the trend of the ***,fracture data of 146 numbers have been collected using Brunton compass to generate rose diagram and were correlated with the rose diagram derived from *** present study significantly brought up

关键词： Hard rock aquifer Artificial recharge remote sensing and GIS Groundwater level