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赋予物理学持久魅力的超流

物理 2024年第5期53卷 352-353页

作者：赵小明刘伍明 Hamish johnston 北京科技大学物理系中国科学院物理研究所

量子效应无处不在，但物质的量子特性往往只在微观层面显现。超流氦却与众不同，它的一些奇异特性可以被直观观察到。在《超流体》一书中，任职于欧洲散裂中子源和隆德大学的工程师约翰·魏森德(John Weisend)阐释了这些特性，它们使得...

量子效应无处不在，但物质的量子特性往往只在微观层面显现。超流氦却与众不同，它的一些奇异特性可以被直观观察到。在《超流体》一书中，任职于欧洲散裂中子源和隆德大学的工程师约翰·魏森德(John Weisend)阐释了这些特性，它们使得这种非凡物质成为众多尖端科技不可或缺的一部分。超流氦不仅仅是科学上的奇趣现象，目前研究人员和工程师正以吨为单位使用它。

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Nitrate reduction capacity of the oral microbiota is impaired in periodontitis:potential implications for systemic nitric oxide availability

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International Journal of Oral Science 2024年第1期16卷 52-61页

作者： Bob T.Rosier William johnston Miguel carda-Diéguez Annabel Simpson Elena Cabello-Yeves Krystyna Piela Robert Reilly Alejandro Artacho Chris Easton Mia Burleigh Shauna Culshaw Alex Mira Department of Genomics and Health FISABIO FoundationCenter for Advanced Research in Public HealthValenciaSpain Department of Biological and Biomedical Sciences Glasgow Caledonian UniversityGlasgowUK Oral Sciences University of Glasgow Dental SchoolSchool of MedicineDentistry and NursingCollege of MedicalVeterinary and Life SciencesUniversity of GlasgowGlasgowUK Sport and Physical Activity Research Institute University of the West of ScotlandBlantyreScotland Instituto de Biomedicina de Valencia Consejo Superior de Investigaciones Científicas(IBV-CSIC)ValenciaSpain CIBER Center for Epidemiology and Public Health MadridSpain

The reduction of nitrate to nitrite by the oral microbiota has been proposed to be important for oral health and results in nitric oxide formation that can improve cardiometabolic conditions. Studies of bacterial composition in subgingival plaque suggest that nitrate-reducing bacteria are associated with periodontal health, but the impact of periodontitis on nitrate-reducing capacity(NRC)and, therefore, nitric oxide availability has not been evaluated. The current study aimed to evaluate how periodontitis affects the NRC of the oral microbiota. First, 16S rRNA sequencing data from five different countries were analyzed, revealing that nitratereducing bacteria were significantly lower in subgingival plaque of periodontitis patients compared with healthy individuals(P < 0.05 in all five datasets with n = 20–82 samples per dataset). Secondly, subgingival plaque, saliva, and plasma samples were obtained from 42 periodontitis patients before and after periodontal treatment. The oral NRC was determined in vitro by incubating saliva with 8 mmol/L nitrate(a concentration found in saliva after nitrate-rich vegetable intake) and compared with the NRC of 15healthy individuals. Salivary NRC was found to be diminished in periodontal patients before treatment(P < 0.05) but recovered to healthy levels 90 days post-treatment. Additionally, the subgingival levels of nitrate-reducing bacteria increased after treatment and correlated negatively with periodontitis-associated bacteria(P < 0.01). No significant effect of periodontal treatment on the baseline saliva and plasma nitrate and nitrite levels was found, indicating that differences in the NRC may only be revealed after nitrate intake. Our results suggest that an impaired NRC in periodontitis could limit dietary nitrate-derived nitric oxide levels, and the effect on systemic health should be explored in future studies.

关键词： impaired intake nitrate

The relationship between DNA fragmentation and the intensity of morphologically abnormal human spermatozoa

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Asian pacific Journal of Reproduction 2024年第1期13卷 22-27页

作者： Mercedes González-Martínez Pascual Sánchez-Martín carmen López-Fernández Stephen D.johnston Jaime Gosálvez Clínica Ginemed Unidad de ReproducciónSevillaSpain Department of Biology Universidad Autónoma de MadridCantoblancoMadridSpain School of Environment The University of QueenslandGattonAustralia School of Veterinary Science The University of QueenslandGattonAustralia

Objective:To determine the relationship between teratozoospermia and sperm DNA fragmentation(SDF)in the human ***:This retrospective study included 100 normozoospermic men as a control cohort(abnormal forms>14%),210 patients with a high level of abnormal forms(≤4%)and 65 patients presenting with a moderate level of abnormal forms(>4%to≤14%)based on the World Health Organization *** morphology was assessed using bright field *** DNA fragmentation was assessed using the sperm chromatin dispersion ***-parametric analyses were conducted to examine the relationship between abnormal sperm morphology and sperm DNA fragmentation;receiver operating characteristic(ROC)analyses were conducted to assess sensitivity and specificity of this ***:A correlation analysis revealed that the higher the proportion of abnormal spermatozoa in the ejaculate,the higher the level of SDF(Spearman's Rho=-0.230;P<0.001).Significant differences in the proportion of SDF were found when all cohorts were compared(P<0.001);these significant differences were also retained when the different cohorts were compared *** analysis showed a moderate but significant predictive value for SDF to differentiate patients with different levels of ***:Although analysis of a more continuous range of values for teratozoospermia would help further clarify any causal relationship with SDF,there is clearly a synergistic or coincident affiliation between these variables that needs to be acknowledged by the clinician when interpreting the spermiogram.

关键词： Teratozoospermia Sperm morphology Sperm DNA fragmentation Male factor Human reproduction Human fertility

A hybrid Monte carlo study of bond-stretching electron–phonon interactions and charge order in BaBiO_(3)

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npj Computational Materials 2023年第1期9卷 1950-1958页

作者： Benjamin Cohen-Stead Kipton Barros Richard Scalettar Steven johnston Department of Physics and Astronomy The University of TennesseeKnoxvilleTN 37996USA Institute for Advanced Materials and Manufacturing The University of TennesseeKnoxvilleTN 37996USA Theoretical Division and CNLS Los Alamos National LaboratoryLos AlamosNM 87545USA Department of Physics and Astronomy University of CaliforniaDavisCA 95616USA

The relationship between electron–phonon(e-ph)interactions and charge-density-wave(CDW)order in the bismuthate family of high-temperature superconductors remains *** address this question using nonperturbative hybrid Monte carlo calculations for the parent compound BaBiO_(3).Our model includes the Bi 6s and O 2pσorbitals and coupling to the Bi-O bond-stretching branch of optical phonons via modulations of the Bi-O hopping *** simulate three-dimensional clusters of up to 4000 orbitals,with input model parameters taken from ab initio electronic structure calculations and a phonon energyℏΩ0=60 *** results demonstrate that the coupling to the bond-stretching modes is sufficient to reproduce the CDW transition in this system,despite a relatively small dimensionless *** also find that the transition deviates from the weak-coupling Peierls’*** work demonstrates that off-diagonal e-ph interactions in orbital space are vital in establishing the bismuthate phase diagram.

关键词： stretching phonon charge

Changes in particulate and mineral-associated organic carbon with land use in contrasting soils

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Pedosphere 2023年第3期33卷 421-435页

作者： Sabina YEASMIN Balwant SINGH Cliff T.johnston Quan HUA Donald L.SPARKS Sydney Institute of Agriculture School of Life and Environmental SciencesThe University of SydneySydney NSW 2006(Australia) Department of Agronomy Bangladesh Agricultural UniversityMymensingh-2202(Bangladesh) Crop Soil and Environmental SciencesPurdue UniversityWest Lafayette IN 47907(USA) Australian Nuclear Science and Technology Organisation Locked Bag 2001Kirrawee DC NSW 2232(Australia) Department of Plant and Soil Sciences University of DelawareNewark DE 19716(USA)

Soil organic carbon(SOC)is the largest terrestrial carbon(C)stock,and the capacity of soils to preserve organic C(OC)varies with many factors,including land use,soil type,and soil *** investigated the effect of land use change on soil particulate organic matter(POM)and mineral-associated organic matter(MOM).Surface(0–10 cm)and subsurface(60–70 cm)samples were collected from paired sites(native and cropped)of four contrasting *** soils were separated into POM and MOM fractions,which were analyzed for mineralogy,OC,nitrogen,isotopic signatures,*** POM fractions of surface soils were relatively unaffected by land use change,possibly because of the continuous input of crop residues,whereas the POM fractions in corresponding subsurface soils lost more *** surface soils,MOM fractions dominated by the oxides of iron and aluminum(oxide-OM)lost more OC than those dominated by phyllosilicates and quartz,which was attributed to diverse organic matter(OM)input and the extent of OC saturation limit of *** contrast,oxide-OM fractions were less affected than the other two MOM fractions in the subsurface soils,possibly due to OC protection via organo-mineral *** deviations in isotopic signature(linked with vegetation)across the fractions suggested that fresh crop residues constituted the bulk of OM in surface soils(supported by greater14C).Increased isotopic signatures and lower14C in subsurface MOM fractions suggested the association of more microbially processed,aged OC with oxide-OM fractions than with the other MOM *** results reveal that the quantity and quality of OC after land use change is influenced by the nature of C input in surface soils and by mineral-organic association in subsurface soils.

关键词： land use change microbial decomposition organic carbon saturation organo-mineral association soil organic matter

Photocatalyst Activity Indicator Inks,paiis,for Assessing Self-Cleaning Films

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Accounts of Materials Research 2022年第1期3卷 67-77页

作者： Andrew Mills James johnston Christopher O’Rourke Andrew Mills−School of Chemistry and Chemical Engineering Queens University BelfastBelfastU.K.BT95AG

CONSPECTUS:Semiconductor photocatalysis,usually referred to simply as“photocatalysis”is a relatively new and yet still a growing subject area,which has led to a billion-dollar industry,mostly focused on the production of self-cleaning architectural materials,such as glass,paint,tiles,fabric,plastic and *** such materials need to be tested for activity,but for self-cleaning activity there are few appropriate tests;the International Standards Organization,ISO,for example,have at present only two,both of which are slow and largely ineffective for most commercial self-cleaning *** photocatalyst community in general,and the manufacturers of self-cleaning photocatalytic products in particular,need a fast,simple,easy to use method of assessing photocatalytic activity,which can also be used to demonstrate the efficacy of self-cleaning materials in minutes,i.e.,a quantitative and qualitative test.

关键词： dollar cleaning architectural

A systematic review and meta-analysis of dietary fat effects on reproductive performance of sows and growth performance of piglets

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Journal of Animal Science and Biotechnology 2022年第3期13卷 662-681页

作者： Lixue Wang Shuai Zhang Lee J.johnston Crystal L.Levesque Jingdong Yin Bing Dong State Key Laboratory of Animal Nutrition College of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193China West Central Research and Outreach Center University of MinnesotaMorrisMN 56267USA Department of Animal Science College of Agriculture and Biological SciencesSouth Dakota State UniversityBrookingsSD 57007USA

Effects of added fat in sow diets on the sows’reproductive performance and offspring growth performance are influenced by multiple factors such as genetics,nutrition,parity,ambient temperatures,and farm *** studies cannot cover all these *** the view to address this challenge,we searched all studies that were published from 1986 to 2020,and performed a systematic review and meta-analysis on the fat *** total,19 papers were collected and *** supplementation in sow diets during late gestation and lactation decreased average daily feed intake(ADFI,P<0.05)and tended to increase average daily energy intake(ADEI,P=0.11).It had no impact on litter weights at birth(P=0.40)or weaning(P=0.46).It increased total numbers of piglets at birth(P=0.07),but had no effect on liveborn per litter(P=0.90)or survival rate(P=0.48)of piglets to *** supplementation had no significant effect on sow body weight loss(P=0.67)or backfat thickness changes(P=0.66),but sows fed diets with added fat had increased milk fat concentration(P=0.03)and shorter wean to estrus intervals(WEI,P=0.01).In specific circumstances,fat supplementation tended to improve growth performance of piglets with low litter weights at birth(P=0.14),or when the sows lost large amounts of body weight during lactation(P=0.11).The level of supplemented fat was 10%and higher would decrease liveborn per litter at neutral temperature(P=0.10).The meta-analysis revealed that fat supplementation to sows diet during late gestation and lactation can be beneficial for sow reproductive performance and litter growth performance.

关键词： Diets Fat Growth performance Piglets Reproductive performance Sows

Brief electrical nerve stimulation enhances intrinsic repair capacity of the focally demyelinated central nervous system

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Neural Regeneration Research 2022年第5期17卷 1042-1050页

作者： Lydia Ayanwuyi Nataliya Tokarska Nikki A.McLean Jayne M.johnston Valerie M.K.Verge Department of Anatomy Physiology and PharmacologyUniversity of SaskatchewanSaskatoonSKCanada Cameco MS Neuroscience Research Center University of SaskatchewanSaskatoonSKCanada

Our lab has shown that brief electrical nerve stimulation(ES)has a dramatic impact on remyelination of lysophosphatidyl choline(LPC)-induced focally demyelinated rat peripheral nerves,while also inducing an axon-protective phenotype and shifting macrophages from a predominantly pro-inflammatory toward a pro-repair *** this same potential exists in the central nervous system is not ***,for proof of principle studies,the peripheral nerve demyelination and ES model was adapted to the central nervous system,whereby a unilateral focal LPC-induced demyelination of the dorsal column at the lumbar enlargement where the sciatic nerve afferents enter was created,so that subsequent ipsilateral sciatic nerve ES results in increased neural activity in the demyelinated *** reveal a robust focal demyelination at 7 days post-LPC *** of 1-hour ES at 7 days post-LPC polarizes macrophages/microglia toward a pro-repair phenotype when examined at 14 days post-LPC;results in smaller LPC-associated regions of inflammation compared to non-stimulated controls;results in significantly more cells of the oligodendroglial lineage in the demyelinated region;elevates myelin basic protein levels;and shifts the paranodal protein Caspr along demyelinated axons to a more restricted distribution,consistent with reformation of the paranodes of the nodes of *** also significantly enhanced levels of phosphorylated neurofilaments detected in the zones of demyelination,which has been shown to confer axon *** these findings support that strategies that increase neural activity,such as brief electrical stimulation,can be beneficial for promoting intrinsic repair following focal demyelinating insults in demyelinating diseases such as multiple *** animal procedures performed were approved by the University of Saskatchewan's Animal Research Ethics Board(protocol#20090087;last approval date:November 5,2020).

关键词： axon protection demyelination immune response lysophosphatidyl choline macrophage microglia multiple sclerosis myelin nervous system repair neural activity polarization

Effects of Reduced Nocturnal Temperature on Performance and Behavior of Nursery Pigs

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Journal of Integrative Agriculture 2012年第9期11卷 1509-1516页

作者： Lee J johnston West Central Research and Outreach Center University of MinnesotaMorris MN 56267 USA

Previous studies suggested that pigs prefer lower environmental temperatures during nighttime compared to daytime. So reducing nocturnal temperature in nursery barns may not jeopardize performance or welfare of pigs, but can save energy for heating the barn. A study was conducted to investigate growth performance and behavioral response of nursery pigs to reduced nocturnal temperature. This study was conducted in four replicates, each utilizing 270 newly weaned pigs and lasting for 5 wk. Temperature setpoint in the control room （CON） was started at 30℃ and decreased by 2℃ per week. In the treatment room （RNT）, temperature setpoint was maintained same as in CON between 7：00 h and 19：00 h, and reduced by 8~C between 19：00 h and 7：00 h starting from d 5. Growth performance （15 pens/room, 9 pigs/pen, BW=（6.3±0.61） kg） was monitored for 5 wk, and behaviors in 6 pens in each room were video-recorded for 24 h 3 d after being exposed to the experimental temperature. Instantaneous scan sampling was performed to determine time budgets for standing, sitting, eating, drinking, belly nosing, three postures of lying, and huddling. Two focal pigs were continuously viewed to record duration and occurrence of eating and drinking. Reduced nocturnal temperature did not affect the growth performance of the pigs, time spent standing, sitting, total lying and eating or duration and frequencies of eating and drinking （all P〉0.10）. However, RNT increased time spent lying sternal （83 vs. 72%, P〈0.001） and number of pigs that were huddling （70 vs. 50% of lying pigs, P〈0.001）, and decreased time spent lying laterally （0.8 vs. 4.6%, P〈0.001）, lying half laterally （5.3 vs. 11.0%, P〈0.001）, and belly nosing （0.9 vs. 1.7%, P=0.01） during nighttime. These results indicate that nursery pigs adopted the posture of lying sternal and huddled together to reduce heat loss from their body surface to maintain thermal balance and growth performance in RNT. Such mild reduction in nocturnal temperature in th

关键词： reduced nocturnal temperature behavior growth performance pigs