Continuous wave and active Q-switched operation of Watt-level LED-pumped two-rod Nd,Ce:YAG laser

A high-performance LED-side-pumped two-rod Nd,Ce:YAG laser with continuous-wave(CW) and acousto–optical(A-O) Q-switched operation is demonstrated in this work. A symmetrically shaped flat–flat cavity with two identical LEDside-pumped laser modules is employed for power scalability. In the CW regime, the maximum output average power of laser at 1064 nm is 4.41 W, corresponding to a maximum optical conversion efficiency of 5.3% and a slope efficiency is 12.4%. In the active Q-switched regime, the pulse energy of laser reaches as high as 0.89 m J at a repetition rate of 800 Hz with a pulse width of 457.2 ns, the corresponding highest peak output power is 1.94 k W and the M~2 factor is measured to be about 8.8. To the best of the authors' knowledge, this is the first demonstration and the highest performance of a CW LED-side-pumped two-rod laser Nd,Ce:YAG with Watt-level output reported so far.

“ACTIVE”英语学科育人模式构建与应用

本研究以“立德树人”为核心理念,构建“ACTIVE”英语学科育人模式。该模式通过六个关键维度--学科育人(AIM)、文化浸润(Culture)、思维可见(Thinking)、技术融合(Integration)、美德根植(Virtue)和情感共鸣(Empathy)--全面激发学生英语学习的热情,培养他们的语言能力,同时注重道德品质的熏陶和文化素养的提升,促进英语学科素养落地。本研究不仅为英语教学实践提供了新的视角,也为其他学科育人模式的构建提供了有益的参考和借鉴。

Continuous-Wave and Actively Q-Switched Diode-Pumped Er:LuAG Ring Laser at 1650 nm

We demonstrate a cw and actively Q-switched Er：LuAO laser resonantly dual-end-pumped by 1532nm fibre- coupled laser diodes. A maximum cw output power of 1.9W at 1650.3nm is obtained at a pump power of 25.5 W, corresponding to a slope efficiency of 43.3 %. In the Q-switched regime, the maximum pulse energy of 3.51 mJ is reached at a pulse repetition rate of 100 Hz, a pulse duration of 90.5ns and a pump power of 25.5 W. At the repetition rate of 400 Hz, the output energy is 2.12m J, corresponding to a pulse duration of 125.4 ns.

2024 Adult Compendium of Physical Activities:A third update of the energy costs of human activities

Background:The Compendium of Physical Activities was published in 1993 to improve the comparability of energy expenditure values assigned to self-reported physical activity(PA)across studies.The original version was updated in 2000,and again in 2011,and has been widely used to support PA research,practice,and public health guidelines.Methods:This 2024 update was tailored for adults 19-59 years of age by removing data from those≥60 years.Using a systematic review and supplementary searches,we identified new activities and their associated measured metabolic equivalent(MET)values(using indirect calorimetry)published since 2011.We replaced estimated METs with measured values when possible.Results:We screened 32,173 abstracts and 1507 full-text papers and extracted 2356 PA energy expenditure values from 701 papers.We added303 new PAs and adjusted 176 existing MET values and descriptions to reflect the addition of new data and removal of METs for older adults.We added a Major Heading(Video Games).The 2024 Adult Compendium includes 1114 PAs(912 with measured and 202 with estimated values)across 22 Major Headings.Conclusion:This comprehensive update and refinement led to the creation of The 2024 Adult Compendium,which has utility across research,public health,education,and healthcare domains,as well as in the development of consumer health technologies.The new website with the complete lists of PAs and supporting resources is available at https://pacompendium.com.

A brief history of the Compendium of Physical Activities

The Compendium of Physical Activities(Compendium)was developed to address consistent assignment of physical activity(PA)intensity values used in PA epidemiology research of the association between PA and health outcomes.1The known protective effects of PA on incident health outcomes traces to the mid-1900s,with over 50 studies examining coronary heart disease(CHD)as the outcome of interest.

High-power xenon lamp-pumped Er:YAP pulse laser operated in free-running and acousto-optical Q-switching modes

We demonstrate a high-energy and high-power pulse laser on a xenon lamp-pumped Er:YAP crystal. The laser performance and thermal focal lengths under different working frequencies are discussed. The results show that the thermal lens effect is gradually aggravated with the increase of working frequencies, and even working at 100 Hz, a single pulse energy of 234 m J can be achieved. A maximum average power of 41.5 W is achieved with a working frequency of 20 Hz and slope efficiency of 2.82%. This output power is much higher than other xenon lamp-pumped erbium laser devices.A Q-switched laser is demonstrated by using the TeO2crystal, the maximum output energies of 11.5 m J and 3.5 m J are obtained at 50 and 100 Hz, the corresponding peak powers are 93.4 k W and 17.2 kW, respectively.The laser wavelengths and beam quality factors are also characterized in the free-running and Q-switched modes. A higher pulse energy and peak power laser could be achieved further by improving the damage threshold of TeO2acousto-optical Q-switching. All the experimental results illustrate that the xenon lamp-pumped Er:YAP laser is a promising candidate for high-power and high-frequency mid-infrared laser devices.

Association between physical activity and risk of gastroesophageal reflux disease:A systematic review and meta-analysis

Background:Lifestyle plays an important role in preventing and managing gastroesophageal reflux disease(GERD).In response to the conflicting results in previous studies,we performed a systematic review and meta-analysis to investigate this association.Methods:Relevant studies published until January 2023 were retrieved from 6 databases,and the prevalence of symptomatic gastroesophageal reflux(GER)or GERD was determined from the original studies.A random effects model was employed to meta-analyze the association by computing the pooled relative risk(RR)with 95%confidence intervals(95%CIs).Furthermore,subgroup and dose-response analyses were performed to explore subgroup differences and the association between cumulative physical activity(PA)time and GERD.Results:This meta-analysis included 33 studies comprising 242,850 participants.A significant negative association was observed between PA and the prevalence of symptomatic GER(RR=0.74,95%CI:0.66-0.83;p<0.01)or GERD(RR=0.80,95%CI:0.76-0.84;p<0.01),suggesting that engaging in PA might confer a protective benefit against GERD.Subgroup analyses consistently indicated the presence of this association across nearly all subgroups,particularly among the older individuals(RR_(<40 years):RR_(≥40 years)=0.85:0.69,p<0.01)and smokers(RR_(smoker):RR_(non-smoker)=0.67:0.82,p=0.03).Furthermore,a dose-response analysis revealed that individuals who engaged in 150 min of PA per week had a 72.09%lower risk of developing GERD.Conclusion:Maintaining high levels of PA decreased the risk of GERD,particularly among older adults and smokers.Meeting the recommended PA level of 150 min per week may significantly decrease the prevalence of GERD.

Association of physical activity with risk of chronic kidney disease in China:A population-based cohort study

Background:Information on the association between physical activity(PA)and the risk of chronic kidney disease(CKD)is limited.We aimed to explore the associations of total,domain-specific,and intensity-specific PA with CKD and its subtypes in China.Methods:The study included 475,376 adults from the China Kadoorie Biobank aged 30-79 years during 2004-2008 at baseline.An interviewer-administered questionnaire was used to collect the information about PA,which was quantified as metabolic equivalent of task hours per day(MET-h/day)and categorized into 4 groups based on quartiles.Cox regression was used to analyze the association between PA and CKD risk.Results:During a median follow-up of 12.1 years,5415 incident CKD cases were documented,including 1159 incident diabetic kidney disease(DKD)cases and 362 incident hypertensive nephropathy(HTN)cases.Total PA was inversely associated with CKD risk,with an adjusted hazard ratio(HR,95%confidence interval(95%CI))of 0.83(0.75-0.92)for incident CKD in the highest quartile of total PA as compared with participants in the lowest quartile.Similar results were observed for risk of DKD and HTN,and the corresponding HRs(95%CIs)were 0.75(0.58-0.97)for DKD risk and 0.56(0.37-0.85)for HTN risk.Increased nonoccupational PA,low-intensity PA,and moderate-to-vigorous-intensity PA were significantly associated with a decreased risk of CKD,with HRs(95%CIs)of 0.80(0.73-0.88),0.85(0.77-0.94),and 0.85(0.76-0.95)in the highest quartile,respectively.Conclusion:PA,including nonoccupational PA,low-intensity PA,and moderate-to-vigorous-intensity PA,was inversely associated with the risk of CKD,including DKD,HTN,and other CKD,and such associations were dose dependent.

Association of accelerometer-measured sleep duration and different intensities of physical activity with incident type 2 diabetes in a population-based cohort study

Purpose:The aim of the current study was to investigate the association of accelerometer-measured sleep duration and different intensities of physical activity(PA)with the risk of incident type 2 diabetes in a population-based prospective cohort study.Methods:Altogether,88,000 participants(mean age=62.2±7.9 years,mean±SD)were included from the UK Biobank.Sleep duration(short:<6 h/day;normal:6-8 h/day;long:>8 h/day)and PA of different intensities were measured using a wrist-won accelerometer over a 7-day period between 2013 and 2015.PA was classified according to the median or World Health Organization-recommendation:total volume of PA(high,low),moderate-to-vigorous PA(MVPA)(recommended,not recommended),and light-intensity PA(high,low).Incidence of type 2diabetes was ascertained using hospital records or death registries.Results:During a median follow-up of 7.0 years,1615 incident type 2 diabetes cases were documented.Compared with normal sleep duration,short(hazard ratio(HR)=1.21,95%confidence interval(95%CI):1.03-1.41)but not long sleep duration(HR=1.01,95%CI:0.89-1.15)was associated with excessive type 2 diabetes risk.This increased risk among short sleepers seems to be protected against by PA.Compared with normal sleepers with high or recommended PA,short sleepers with low volume of PA(HR=1.81,95%CI:1.46-2.25),not recommended(below the World Health Organization-recommended level of)MVPA(HR=1.92,95%CI:1.55-2.36),or low light-intensity PA(HR=1.49,95%CI:1.13-1.90)had a higher risk of type 2 diabetes,while short sleepers with a high volume of PA(HR=1.14,95%CI:0.88-1.49),recommended MVPA(HR=1.02,95%CI:0.71-1.48),or high light-intensity PA(HR=1.14,95%CI:0.92-1.41)did not.Conclusion:Accelerometer-measured short but not long sleep duration was associated with a higher risk of incident type 2 diabetes.A higher level of PA,regardless of intensity,potentially ameliorates this excessive risk.

The association of diet quality and physical activity with cardiovascular disease and mortality in 85,545 older Australians:A longitudinal study

Background:A quality diet and an active lifestyle are both important cornerstones of cardiovascular disease(CVD)prevention.However,despite their interlinked effects on metabolic health,the 2 behaviors are rarely considered jointly,particularly within the context of CVD prevention.We examined the independent,interactive,and joint associations of diet and physical activity with CVD hospitalization,CVD mortality,and all-cause mortality.Methods:CVD-free Australian participants aged 4574 years(n=85,545)reported physical activity,diet,sociodemographic,and lifestyle characteristics at baseline(20062009)and follow-up(20122015),and data were linked to hospitalization and death registries(03/31/2019 for CVD hospitalization and all-cause mortality and 12/08/2017 for CVD mortality).Diet quality was categorized as low,medium,and high based on meeting dietary recommendations.Physical activity was operationalized as(a)total moderate-to-vigorous physical activity(MVPA)as per guidelines,and(b)the composition of MVPA as the ratio of vigorous-intensity physical activity(VPA)to total MVPA.We used a left-truncated cause-specific Cox proportional hazards model using time-varying covariates.Results:During a median of 10.7 years of follow-up,6576 participants were admitted to the hospital for CVD and 6581 died from all causes(876 from CVD during 9.3 years).A high-quality diet was associated with a 17%lower risk of all-cause mortality than a low-quality diet,and the highest MVPA category(compared with the lowest)was associated with a 44%and 48%lower risk of CVD and all-cause mortality,respectively.Multiplicative interactions between diet and physical activity were non-significant.For all outcomes,the lowest risk combinations involved a high-quality diet and the highest MVPA categories.Accounting for total MVPA,some VPA was associated with further risk reduction of CVD hospitalization and all-cause mortality.Conclusion:For CVD prevention and longevity,one should adhere to both a healthy diet and an active lifestyle and incorporate some VPA when possible.

Association of daily sitting time and leisure-time physical activity with body fat among U.S.adults

Background:Prolonged sitting and reduced physical activity lead to low energy expenditures.However,little is known about the joint impact of daily sitting time and physical activity on body fat distribution.We investigated the independent and joint associations of daily sitting time and physical activity with body fat among adults.Methods:This was a cross-sectional analysis of U.S.nationally representative data from the National Health and Nutrition Examination Survey2011-2018 among adults aged 20 years or older.Daily sitting time and leisure-time physical activity(LTPA)were self-reported using the Global Physical Activity Questionnaire.Body fat(total and trunk fat percentage)was determined via dual X-ray absorptiometry.Results:Among 10,808 adults,about 54.6%spent 6 h/day or more sitting;more than one-half reported no LTPA(inactive)or less than 150 min/week LTPA(insufficiently active)with only 43.3%reported 150 min/week or more LTPA(active)in the past week.After fully adjusting for sociodemographic data,lifestyle behaviors,and chronic conditions,prolonged sitting time and low levels of LTPA were associated with higher total and trunk fat percentages in both sexes.When stratifying by LTPA,the association between daily sitting time and body fat appeared to be stronger in those who were inactive/insuufficiently active.In the joint analyses,inactive/insuufficiently active adults who reported sitting more than 8 h/day had the highest total(female:3.99%(95%confidence interval(95%CI):3.09%-4.88%);male:3.79%(95%CI:2.75%-4.82%))and trunk body fat percentages(female:4.21%(95%CI:3.09%-5.32%);male:4.07%(95%CI:2.95%-5.19%))when compared with those who were active and sitting less than 4 h/day.Conclusion:Prolonged daily sitting time was associated with increased body fat among U.S.adults.The higher body fat associated with 6 h/day sitting may not be offset by achieving recommended levels of physical activity.

Variation in the permafrost active layer over the Tibetan Plateau during 1980–2020

The active layer,acting as an intermediary of water and heat exchange between permafrost and atmosphere,greatly influences biogeochemical cycles in permafrost areas and is notably sensitive to climate fluctuations.Utilizing the Chinese Meteorological Forcing Dataset to drive the Community Land Model,version 5.0,this study simulates the spatial and temporal characteristics of active layer thickness(ALT)on the Tibetan Plateau(TP)from 1980 to 2020.Results show that the ALT,primarily observed in the central and western parts of the TP where there are insufficient station observations,exhibits significant interdecadal changes after 2000.The average thickness on the TP decreases from 2.54 m during 1980–1999 to 2.28 m during 2000–2020.This change is mainly observed in the western permafrost region,displaying a sharp regional inconsistency compared to the eastern region.A persistent increasing trend of ALT is found in the eastern permafrost region,rather than an interdecadal change.The aforementioned changes in ALT are closely tied to the variations in the surrounding atmospheric environment,particularly air temperature.Additionally,the area of the active layer on the TP displays a profound interdecadal change around 2000,arising from the permafrost thawing and forming.It consistently decreases before 2000 but barely changes after 2000.The regional variation in the permafrost active layer over the TP revealed in this study indicates a complex response of the contemporary climate under global warming.

Efficient Diode-End-Pumped Actively Q-Switched Nd:YLF/SrWO4 Raman Laser

An efficient diode-end-pumped actively Q-switched Nd：YLF/SrW04 Raman laser is demonstrated. The fun- damental wave is 1047.0nm and the corresponding first-Stocks wave is 1158.7nm. With a pumping power of 10.5 W, the average output power of 2.2 W at 1158.7nm is obtained, with the corresponding optical conversion efficiency of 20.9%. At a repetition rate of 6 kHz, the pulse width of the Raman laser is 8. 7ns and the peak power is calculated to be 42.1 kW. The beam quality factors M2 in horizontal and vertical directions are 1.3 and 1.5, respectively.

A Mid-IR Optical Parametric Oscillator Pumped by an Actively Q-Switched Ho:YAG Ceramic Laser

We demonstrate a mid-IR ZnGeP2 （ZGP） optical parametric oscillator （OPO） pumped by a dual-end-pumped actively aeoasto-optie Q-switched Ho：YAG ceramic laser. The maximum average output power of 35 W is obtained at a pulse repetition frequency of 20 kHz from the Ho：YAG ceramic laser. Under the maximum incident pump power of Ho：YAG ceramic laser, the maximum output power of 14 W is obtained from the ZGP OPO, corresponding to the slope efficiency of 49.6% with respect to the incident pump power. The wavelength can be tuned from 3.5 μm to 4.2μm （signal）, corresponding to 5.24.1 μm （idler）. The beam quality M2 is less than 2.3 from the ZGP OPO.

Efficient Diode-Pumped Actively Q-Switched Ceramic Nd:YAG/YVO4 Raman Laser Operating at 1657 nm

A diode-pumped actively Q-switched Raman laser is demonstrated, with YV04 employed as Raman active medium, based on a ceramic Nd：YAG laser operating at 1444nm. The first-stokes Raman generation at 1657nm is achieved. A maximum output power of as high as 612mW is obtained under a pump power of 20. 7 W and at a pulse repetition frequency rate of 20kHz, corresponding to an optical-to-optical conversion efficiency of 3%.

Bridging the gap:Unveiling the crisis of physical inactivity in inflammatory bowel diseases

In this editorial we comment on the article titled“Inflammatory bowel diseases patients suffer from significant low levels and barriers to physical activity:The BE-FIT-IBD study”published in a recent issue of the World Journal of Gastroen-terology 2023;29(41):5668-5682.Inflammatory bowel diseases(IBD)are emerging as a significant global health concern as their incidence continues to rise on a global scale,with detrimental impacts on quality of life.While many advances have been made regarding the management of the disease,physical inactivity in these patients represents an underexplored issue that may hold the key for further and better understanding the ramifications of IBD.Chronic pain,fatigue,and fear of exacerbating symptoms promotes physical inactivity among IBD patients,while the lack of clear guidelines on safe exercise regimens contributes to a norm of physical inactivity.Physical activity(PA)is accepted to have a positive effect on disease outcomes and quality of life,while inactivity exacerbates comorbidities like cardiovascular disease and mental health disorders.The“BE-FIT-IBD”study,focusing on PA levels and barriers in IBD patients of Southern Italy,revealed that a significant proportion(42.9%)were physically inactive.This lack of PA is attributed to barriers such as fear of flare-ups and misconceptions about exercise exacerbating the disease.The study also highlighted the need for better communication between healthcare providers and patients regarding the benefits of PA and safe incorporation into lifestyles.Moreover,physical inactivity may also contribute to disability in IBD patients,having a great impact on employment status.Of note is the fact that IBD also comes with an important psychological burden with relevant evidence suggesting that regular PA can improve mood,reduce anxiety,and enhance mental health.The“BE-FIT-IBD”study advocated for the integration of PA into IBD management,emphasizing the bidirectional link between PA and IBD.Regular exercise can influence the course of IBD,potentially reducing symptom severity and prolonging remission periods.As such,it is mandatory that healthcare providers actively educate patients,dispel misconceptions,and tailor exercise recommendations to improve the quality of life and reduce IBD-related complications.

Interaction between inflammatory bowel disease,physical activity,and myokines:Assessment of serum irisin levels

Inflammatory bowel disease(IBD),including Crohn’s disease and ulcerative colitis,showed a wide spectrum of intestinal and extra-intestinal manifestations,which rendered the patients physically inactive and impaired their quality of life.It has been found that physical activity is a non-pharmacological intervention that improves the quality of life for those patients.Irisin is one member of the myokines secreted by muscle contraction during exercise and could be used as an antiinflammatory biomarker in assessing the physical activity of IBD patients.In addition,experimental studies showed that exogenous irisin significantly decreased the inflammatory markers and the histological changes of the intestinal mucosa observed in experimental colitis.Furthermore,irisin produces changes in the diversity of the microbiota.Therefore,endogenous or exogenous irisin,via its anti-inflammatory effects,will improve the health of IBD patients and will limit the barriers to physical activity in patients with IBD.

High-Power Dual-End-Pumped Actively Q-Switched Ho:YAG Ceramic Laser

We present a high-power Ho：YAG ceramic laser pumped at 1908nm. Using a dual-end-pumped structure, the maximum continuous-wave output power of 48 W is obtained, corresponding to a slope efficiency of 70.4% with respect to the absorbed pump power. At actively Q-switched mode, the maximum average output power of 46 W and the minimum pulse width of 21 ns are achieved at a pulse repetition frequency of 20 kHz, corresponding to a peak power of approximately 109.5kW. In addition, the beam-quality M2 factor is found to be 1.4 at the maximum output power.

Structure and immunomodulatory activity of Lentinus edodes polysaccharides modified by probiotic fermentation

Plant-based fermentations provide an untapped source for novel biotechnological applications.In this study,a probiotic named Lactobacillus fermentum 21828 was introduced to ferment Lentinus edodes.Polysaccharides were extracted from fermented and non-fermented L.edodes and purified via DEAE-52 and Sephadex G-100.The components designated F-LEP-2a and NF-LEP-2a were analyzed by FT-IR,HPGPC,HPAEC,SEM,GC-MS and NMR.The results revealed that probiotic fermentation increased the molecular weight from 1.16×10^(4) Da to 1.87×10^(4) Da and altered the proportions of glucose,galactose and mannose,in which glucose increased from 45.94%to 48.16%.Methylation analysis and NMR spectra indicated that F-LEP-2a and NF-LEP-2a had similar linkage patterns.Furthermore,their immunomodulatory activities were evaluated with immunosuppressive mice.NF-LEP and F-LEP improved immune organ indices,immunoglobulin(Ig G and Ig M)and cytokines concentrations;restored the antioxidation capacity of liver;and maintained the balance of gut microbiota.F-LEP displayed better moderating effects on the spleen index,immunoglobulin,cytokines and the diversity of gut microbiota than NF-LEP(200,400 mg/kg).Our study provides an efficient and environment-friendly way for the structural modification of polysaccharides,which helps to enhance their biological activity and promote their wide application in food,medicine and other fields.

Liquid crystal-integrated metasurfaces for an active photonic platform

Metasurfaces have opened the door to next-generation optical devices due to their ability to dramatically modulate electromagnetic waves at will using periodically arranged nanostructures.However,metasurfaces typically have static optical responses with fixed geometries of nanostructures,which poses challenges for implementing transition to technology by replacing conventional optical components.To solve this problem,liquid crystals(LCs)have been actively employed for designing tunable metasurfaces using their adjustable birefringent in real time.Here,we review recent studies on LCpowered tunable metasurfaces,which are categorized as wavefront tuning and spectral tuning.Compared to numerous reviews on tunable metasurfaces,this review intensively explores recent development of LC-integrated metasurfaces.At the end of this review,we briefly introduce the latest research trends on LC-powered metasurfaces and suggest further directions for improving LCs.We hope that this review will accelerate the development of new and innovative LC-powered devices.