Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42
Filtrar
1.
Opt Express ; 32(7): 11895-11906, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38571027

RESUMO

Pure-quartic solitons (PQSs) have recently received increasing attention due to their energy-width scaling over the traditional soliton, which has expanded our understanding of soliton dynamics with high-order dispersion in nonlinear systems. Here, we numerically reveal the asynchronization and synchronization processes of the sub-pulse within the vector PQS molecule in a mode-locked fiber laser by solving the coupled Ginzburg-Landau equations. During the establishment of a vector PQS molecule, the repulsion, attraction, and finally stabilization processes have been observed. Specifically, sub-pulse disappearance, regeneration, and finally synchronization with the other pulses are also investigated. Our analysis of the pulse energy, time interval, and relative phase evolution dynamics with the round trip indicates that the asynchronization and synchronization within the vector PQS molecule associate tightly with the gain competition and the cross-phase modulation. Our findings provide insights into the internal mutual dynamics within the vector soliton molecule and offer guidance for the applications of PQS.

2.
Opt Express ; 32(6): 9397-9404, 2024 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-38571175

RESUMO

This research proposed a novel pulse-shaping design for directly shaping distorted pulses after the amplification. Based on the principle of the design we made a pulse shaper. With this pulse shaper, we successfully manipulate the pulse's leading edge and width to achieve an 'M'-shaped waveform in an amplification system. Comparative experiments were conducted within this system to compare the output with and without the integration of the pulse shaper. The results show a significant suppression of the nonlinear effect upon adding the pulse shaper. This flexible and effective pulse shaper can be easily integrated into a high-power all-fiber system, supplying the capability to realize the desired output waveform and enhance the spectral quality.

3.
BMJ Open ; 14(3): e071513, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38448067

RESUMO

OBJECTIVES: This study sought to examine the relationship between Toxoplasma gondii seropositivity and cognitive function in older adults. DESIGN: An observational cross-sectional study. SETTING: The National Health and Nutrition Examination Survey (NHANES) study took place at participants' homes and mobile examination centres. PARTICIPANTS: A total of 2956 older adults aged 60 and above from the NHANES from 2011 to 2014 were included in the study. Exposure of interest: participants had serum Toxoplasma gondii antibody analysed in the laboratory. A value>33 IU/mL was categorised as seropositive for Toxoplasma gondii infection; <27 IU/mL was categorised as seronegative for Toxoplasma gondii infection. PRIMARY AND SECONDARY OUTCOME MEASURES: Cognitive tests included the Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest (CERAD-WL) for immediate and delayed memory, the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). RESULTS: About half of the 2956 participants (mean age 70.0) were female (51.0%), non-Hispanic White (48.3%), and completed some college or above (48.3%). A total of 703 participants were positive for Toxoplasma gondii infection (23.8%). Adjusted linear regression showed that compared with participants with negative Toxoplasma gondii infection, those with positive Toxoplasma gondii infection had lower CERAD-WL immediate memory (beta (ß) -0.16, 95% CI -0.25 to -0.07), CERAD-WL delayed memory (ß -0.15, 95% CI -0.24 to -0.06), AFT (ß -0.15, 95% CI -0.24 to -0.06), DSST (ß -0.34, 95% CI -0.43 to -0.26), and global cognition (ß -0.24, 95% CI -0.32 to -0.16) z-scores after controlling for the covariates. CONCLUSIONS: Toxoplasma gondii seropositivity is associated with worse immediate and delayed verbal learning, language proficiency, executive functioning, processing speed, sustained attention, working memory, as well as global cognition in older adults. Public health measures aiming at preventing Toxoplasma gondii infection may help preserve cognitive functioning in older adults.


Assuntos
Doença de Alzheimer , Toxoplasma , Toxoplasmose , Animais , Feminino , Humanos , Idoso , Masculino , Estudos Transversais , Inquéritos Nutricionais , Cognição , Toxoplasmose/epidemiologia
4.
Opt Express ; 32(2): 2124-2131, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38297749

RESUMO

This paper provides a method to effectively suppress the severe ASE self-saturation when achieving high repetition frequency tunability with high output power and narrow pulse width in active Q-switched all-fiber lasers. By studying the regularity of the system's multi-stable state, we first ensured that the laser system operated in a steady state. Then output avoids uneven distribution of pulse energy or missing pulses due to period bifurcation state or chaos state. By adding multiple gain sub-rings within the cavity, the sub-ring structure itself indirectly mitigates the ASE self-saturation while smoothing the pulse. The method will avoid the severe power loss caused by traditional smoothing methods by adjusting the AOM rising edge time. It will also avoid lowering the ASE lasing threshold at high repetition frequency. Meanwhile, the intra-cavity backward ASE can be effectively absorbed by inserting the gain fiber in the sub-rings to directly mitigate the ASE self-saturation. The system's continuously adjustable repetition frequency can be as high as over 300 kHz. It ensures that output power above the watt level and a < 0.2 nm narrow bandwidth can be maintained while tuning the repetition frequency. The narrowest smoothing pulse width of 28 ns has been reached.

5.
Food Funct ; 15(1): 355-371, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38093628

RESUMO

Background: Circulatory imbalance of trace elements is frequent in end-stage renal disease (ESRD), leading to a deficiency of essential elements and excess of toxic elements. The present study aimed to investigate whether inulin-type fructans (ITFs) could ameliorate the circulatory imbalance by modulating gut microbiota and regulating the absorption and elimination of trace elements. Methods: Peritoneal dialysis patients were enrolled in a randomized crossover trial, undergoing interventions with ITFs (10 g d-1) and maltodextrin (placebo) over a 9-month period (with a 3-month washout). The primary outcomes included essential elements Mn, Fe, Co, Cu, Zn, Se, Sr, and Mo and potential toxic elements V, Cr, Ni, As, Cd, Ba, Tl, Pb, Th, and U in plasma. Secondary outcomes included the gut microbiome, short chain fatty acids (SCFAs), bile acids (BAs), and daily removal of trace elements through urine, dialysate and feces. Results: Among the 44 participants initially randomized, 29 completed the prebiotic, placebo or both interventions. The daily dietary intake of macronutrients and trace elements remained consistent throughout the study. The administration of 10 g d-1 ITFs significantly reduced plasma arsenic (As) by 1.03 µg L-1 (95%CI: -1.74, -0.33) (FDR-adjusted P = 0.045) down from the baseline of 3.54 µg L-1 (IQRs: 2.61-4.40) and increased the As clearance rate by urine and dialysis (P = 0.033). Positive changes in gut microbiota were also observed, including an increase in the Firmicutes/Bacteroidetes ratio (P = 0.050), a trend towards higher fecal SCFAs (P = 0.082), and elevated excretion of primary BAs (P = 0.035). However, there were no significant changes in plasma concentrations of other trace elements or their daily removal by urine, dialysis and feces. Conclusions: The daily administration of 10 g d-1 ITFs proved to be effective in reducing the circulating retention of As but demonstrated to be ineffective for other trace elements in ESRD. These sentences are ok to include but as "The clinical trial registry number is ChiCTR-INR-17013739 (https://www.chictr.org.cn/showproj.aspx?proj=21228)".


Assuntos
Arsênio , Falência Renal Crônica , Oligoelementos , Humanos , Prebióticos , Inulina , Estudos Cross-Over , Falência Renal Crônica/tratamento farmacológico , Frutanos
6.
Front Neurol ; 14: 1148150, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38107641

RESUMO

Background: Peripheral neuropathy (PN) is prevalent in people with human immunodeficiency virus (PHIV) with no Food and Drug Administration-approved treatment. Therapeutic Chinese massage (TCM) is a promising noninvasive and non-harmful intervention for HIV-related PN. However, relevant research is lacking. The purpose of this study is to evaluate the feasibility of TCM for HIV-related PN. Method: We conducted a pilot, single-centered, two-arm, double-blinded, randomized controlled trial. Twenty eligible PHIV were recruited primarily from the AIDS Foundation Houston, Inc. in Texas and were randomly assigned into two groups. Ten participants in the intervention group received three weekly 25-min TCM sessions by a certified TCM therapist. The remaining ten control group participants received the same therapist's three weekly 25-min placebo massage sessions on their lower extremities. The outcome was the feasibility of this study as measured by recruitment and completion rates, participant safety, and treatment adherence and compliance, as well as the effect size of the intervention. Results: The study population comprised 20 PHIV (mean age 55.23). This study showed high feasibility as measured by a high rate of recruitment, a 100% rate of completion, and zero serious adverse events. As we inquired 21 respondents for eligibility for the study, all except one had HIV-related PN. All respondents were willing to participate in the study and adhered to the group assignment after they enrolled in the study. The participants' baseline pain was at a medium to a high level (6.30 [2.15] out of 10). Conclusion: Chinese massage is a feasible intervention in PHIV. Future relevant randomized controlled trials are expected. Clinical trial registration: https://clinicaltrials.gov/, NCT05379140.

7.
Opt Express ; 31(22): 35529-35541, 2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-38017721

RESUMO

Pure-quartic soliton (PQS) fiber lasers provide a promising avenue for exploring novel soliton interaction dynamics and generating high-energy pulses. Here, we present the numerical observation of vector PQSs generation and the evolution dynamics in a mode-locked fiber laser, using the coupled Ginzburg-Landau equations. We investigate the buildup dynamics of vector PQSs in a mode-locked laser with birefringent fibers, passing through three stages: energy amplification, energy pulsation owing to the cross-phase modulation (XPM) effect, and finally stabilization. Depending on the strength of the cavity-birefringence, the evolution of PQSs in non-polarization-maintaining fibers reveals that both the elliptical-polarization vector PQSs and near-linear-polarization vector PQSs can be formed by the energy conservation and balance between the two orthogonal directions. Additionally, we observe the transition process from vector PQSs to scalar PQSs with higher cavity-birefringence, resulting from the failure compensation of the walk-off via the soliton trapping effect between the two orthogonal components. These results provide valuable insights into the ultrafast transient process of vector solitons and enhance the understanding of PQS generation in fiber lasers.

8.
Am J Clin Nutr ; 118(1): 264-272, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37146758

RESUMO

BACKGROUND: Although increasing evidence suggests that polyphenol helps regulate blood pressure (BP), evidence from large-scale and long-term population-based studies is still lacking. OBJECTIVES: This study aimed to investigate the association between dietary polyphenol and hypertension risk in the China Health and Nutrition Survey (N = 11,056). METHODS: Food intake was assessed using 3-d, 24-h dietary recalls and household weighing method; polyphenol intake was calculated by multiplying consumption of each food and its polyphenol content. Hypertension was defined as BP ≥ 140/90 mmHg, physicians' diagnosis, or taking antihypertension medications. HR and 95% CI were estimated using mixed-effects Cox models. RESULTS: During 91,561 person-years of follow-up, a total of 3866 participants developed hypertension (35%). The lowest multivariable-adjusted HR (95% CI) of hypertension risk occurred in the third quartile intake, which was 0.63 (0.57, 0.70) for total polyphenol, 0.61 (0.55, 0.68) for flavonoid, 0.62 (0.56, 0.69) for phenolic acid, 0.46 (0.42, 0.51) for lignan, and 0.58 (0.52, 0.64) for stilbene, compared with the lowest quartile. The polyphenol-hypertension associations were nonlinear (all Pnonlinearity < 0.001), and different patterns were observed. U-shaped relations with hypertension were observed for total polyphenol, flavonoid, and phenolic acid, whereas L-shaped associations were observed for lignan and stilbene. Moreover, higher fiber intake strengthened the polyphenol-hypertension association, especially for lignan (P-interaction = 0.002) and stilbene (P-interaction = 0.004). Polyphenol-containing food, particularly vegetables and fruits rich in lignan and stilbene, were significantly associated with lower hypertension risk. CONCLUSIONS: This study demonstrated an inverse and nonlinear association between dietary polyphenol, especially lignan and stilbene, and hypertension risk. The findings provide implications for hypertension prevention.


Assuntos
Hipertensão , Lignanas , Humanos , Polifenóis/análise , Estudos de Coortes , Dieta/métodos , Flavonoides , Hipertensão/epidemiologia , Hipertensão/etiologia , Ingestão de Alimentos , China/epidemiologia
9.
Opt Express ; 31(10): 16845-16856, 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37157754

RESUMO

This paper presents a comprehensive experimental study of multi-stable-state output characteristics in an all-fiber laser with an acoustic-optical modulator (AOM) as the Q-switcher. For the first time, in this structure, the partitioning of the pulsed output characteristics is explored, dividing the operating status of the laser system into four zones. The output characteristics, the application prospects, and the parameter setting rules for working in stable zones are presented. In the second stable zone, a peak power of 4.68 kW with 24 ns was obtained at 10 kHz. This is the narrowest pulse duration achieved with an AOM actively Q-switched all-fiber linear structure. The pulse narrowing is attributed to the rapid release of signal power and pulse tail truncated by AOM shutdown.

10.
Tob Induc Dis ; 21: 68, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37252031

RESUMO

INTRODUCTION: Tobacco contains carcinogens called tobacco-specific nitrosamines. Among the tobacco-specific nitrosamines, is nicotine-derived nitrosamine ketone (NNK) which produces the metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). We aimed to examine the association between urinary tobacco-specific NNAL and cognitive functioning among older adults. METHODS: A total of 1673 older adults aged ≥60 years from the National Health and Nutrition Examination Survey 2013-2014 were included. Urinary tobacco-specific NNAL was analyzed in the laboratory. Cognitive functioning was measured using the Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest (CERAD-WL) immediate and delayed memory tests, the Animal Fluency test (AFT), and the Digit Symbol Substitution Test (DSST). Test-specific and global cognition z-scores were calculated based on means and standard deviations of the cognitive test scores. Multivariable linear regression models were constructed to examine the independent association between quartiles of urinary tobacco-specific NNAL and cognitive test-specific and global cognition z-scores controlling for age, sex, race/ethnicity, education level, depressive symptoms, body mass index, systolic blood pressure, urinary creatinine, hypertension, diabetes, alcohol use, and smoking status. RESULTS: About half of the participants (mean age 69.8 years) were female (52.1%), non-Hispanic White (48.3%), and completed some college and above (49.7%). Multivariable linear regression results showed that participants in the 4th quartile (highest quartile) of urinary NNAL, compared with those in the 1st quartile (lowest quartile), had lower DSST z-scores (ß= -0.19; 95% CI: -0.34 - -0.04). CONCLUSIONS: Tobacco-specific NNAL was negatively associated with processing speed, sustained attention, and working memory in older adults.

11.
Front Neurosci ; 17: 1180782, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37139533

RESUMO

Introduction: In this study, we investigated the relationship between serum lead levels and cognitive functioning in a sample of older adults in the US. Method: Using the National Health and Nutrition Examination Survey (NHANES) 2011-2013, a total of 768 older adults aged ≥60 years were included in the analysis. Lead concentrations in the whole blood samples were assessed using mass spectrometry. We used the immediate and delayed memory portions of the Consortium to Establish a Registry for Alzheimer's Disease Word Learning Subtest (CERAD-WL), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST) to assess the participants' cognitive performance. Using sample averages and standard deviations (SDs), we computed test-specific and global cognition z-scores. To assess the relationships between the quartiles of serum lead levels and cognitive performance, we built multiple linear regression models and adjusted for covariates, including age, sex, race/ethnicity, education, depressive symptoms, alcohol usage, and body mass index. Results: The average age of the participants was 69.6 (SD 6.6) years. Approximately half of the participants were women (52.6%), non-Hispanic white (52.0%), and had completed at least some college education (51.8%). The average serum lead concentration was 1.8 g/dL (SD 1.6) for these participants. The results of multiple linear regression using individuals in the lowest serum lead quantile as a reference group revealed that the serum lead level was not associated with test-specific (CERAD-WL, AFT, and DSST) or global cognitive z-scores. Conclusions: In older adults, concurrent serum lead concentration is not related to cognitive performance. Early or continuous lead exposure may exert a greater effect on the etiology of accelerated cognitive decline with old age.

12.
Front Neurosci ; 17: 1200763, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37207178

RESUMO

Introduction: Serum Cystatin C level, an indication of kidney function, has been implicated in the pathogenesis of Alzheimer's disease and cognitive impairment. In this cross-sectional study, we looked into the relation between serum Cystatin C levels and cognition in a group of U.S. older adults. Method: The data of this study were from the National Health and Nutrition Examination Survey (NHANES) 1999-2002. A total of 4,832 older adults aged ≥60 who met the inclusion criteria were included. The Dade Behring N Latex Cystatin C assay, which is a particle-enhanced nephelometric assay (PENIA), was utilized to assess Cystatin C levels in participants' blood samples. Participants' cognition was examined using the digit symbol substitution test (DSST). Z-scores of the DSST were calculated based on sample means and standard deviations (SD). To investigate the relationships between the quartiles of serum Cystatin C level and DSST z scores, multiple linear regression models were developed while controlling for age, sex, race/ethnicity, and education. Results: The average age of the participants was 71.1 (SD 7.8). The participants were about half female (50.5%), non-Hispanic White (61.2%), and (36.1%) who had completed at least some college. They had an average serum Cystatin C level of 1.0 mg/dl (SD 0.44). After performing multiple linear regression with a reference group consisting of participants in quartile one of plasma Cystatin C levels, we found that serum Cystatin C levels in quartiles three and four were independently associated with lower DSST z scores (ß = -0.059, 95% CI -0.200 to -0.074 and ß = -0.108, 95% CI -0.319 to -0.184, respectively). Conclusion: Higher serum Cystatin C level is associated with worse processing speed, sustained attention, and working memory in older adults. Cystatin C level may be a biomarker for cognitive decline in older adults.

13.
J Nanobiotechnology ; 21(1): 141, 2023 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-37120637

RESUMO

Since the end of 2019, a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has deprived numerous lives worldwide, called COVID-19. Up to date, omicron is the latest variant of concern, and BA.5 is replacing the BA.2 variant to become the main subtype rampaging worldwide. These subtypes harbor an L452R mutation, which increases their transmissibility among vaccinated people. Current methods for identifying SARS-CoV-2 variants are mainly based on polymerase chain reaction (PCR) followed by gene sequencing, making time-consuming processes and expensive instrumentation indispensable. In this study, we developed a rapid and ultrasensitive electrochemical biosensor to achieve the goals of high sensitivity, the ability of distinguishing the variants, and the direct detection of RNAs from viruses simultaneously. We used electrodes made of MXene-AuNP (gold nanoparticle) composites for improved sensitivity and the CRISPR/Cas13a system for high specificity in detecting the single-base L452R mutation in RNAs and clinical samples. Our biosensor will be an excellent supplement to the RT-qPCR method enabling the early diagnosis and quick distinguishment of SARS-CoV-2 Omicron BA.5 and BA.2 variants and more potential variants that might arise in the future.


Assuntos
COVID-19 , Nanopartículas Metálicas , Humanos , SARS-CoV-2/genética , COVID-19/diagnóstico , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Ouro , Mutação , RNA
14.
BMJ Open ; 13(3): e068974, 2023 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-36858467

RESUMO

OBJECTIVES: This study sought to examine the relationship between seropositivity for toxocariasis and cognitive functioning in a nationally representative sample of US older adults. DESIGN: A cross-sectional study. SETTING: National Health and Nutrition Examination Survey (NHANES) data collection took place in the US at participants' homes and mobile examination centres with specialised equipment. PARTICIPANTS: The study population consisted of 3188 community-dwelling US older adults aged 60 and above from the NHANES 2011 to 2014. OUTCOME MEASURES: IgG antibody against Toxocara spp was tested by a Luminex assay using recombinant rTc-CTL-1 antigen. A value >23.1 mean fluorescence intensity (MFI) indicated positive for toxocariasis and a value ≤23.1 MFI as negative for toxocariasis. The Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest immediate and delayed memory, the Animal Fluency test and the Digit Symbol Substitution Test (DSST) were used to assess cognitive functioning. Cognitive test-specific and global cognitive z scores were computed using sample means and SD. RESULTS: The study population consisted of 3188 participants who represented a total of 111 896 309 civilian citizens in the USA. The mean age of the participants was 69.6 years (standard deviation 6.8). The prevalence of toxocariasis in this population was 7.3% (95% confidence interval [CI] 6.1% to 8.5%). The survey-weighted linear regression model showed that compared with participants who were toxocariasis seronegative, those who were seropositive had lower DSST z score (beta [ß] = -0.12, 95% CI -0.22 to -0.01) and global cognition z score (ß=-0.11, 95% CI -0.22 to -0.01), after controlling for age, sex, race/ethnicity, education, depressive symptoms, smoking status, body mass index, prevalent coronary heart disease, prevalent stroke, and systolic blood pressure, physical activity, and total cholesterol. CONCLUSIONS: In our study, seropositive toxocariasis was independently and significantly associated with worse working memory, sustained attention, processing speed and global cognition in older adults. If this association is causal, public health measures to prevent human toxocariasis might help protect older adults' cognitive function.


Assuntos
Toxocaríase , Animais , Humanos , Idoso , Inquéritos Nutricionais , Estudos Transversais , Cognição , Velocidade de Processamento
15.
Mol Nutr Food Res ; 67(9): e2200531, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36855809

RESUMO

SCOPE: Trimethylamine N-oxide (TMAO), an important proatherogenic uremic toxin, is oxidized by hepatic-flavin monooxygenases from gut microbiome-generated trimethylamine (TMA). The present study aims to explore whether manipulating the gut microbiota by inulin-type fructans (ITFs) can reduce circulating TMAO levels in peritoneal dialysis patients. METHODS AND RESULTS: This is a randomized, double-blind, placebo-controlled, crossover trial with 10 g day-1 ITFs intervention for 3 months in continuous ambulatory peritoneal dialysis patients. The gut microbiome is measured, and TMA-producing gene clusters are annotated using shotgun metagenomic sequencing. Fecal and plasma TMA, plasma TMAO, and daily urine excretion and dialysis removal of TMAO are measured. Finally, 22 participants complete the trial. The daily intake of macronutrients and TMAO precursors is comparable during the prebiotics, washout, and placebo interventions. The ITFs intervention increases the Firmicutes/Bacteroidetes (F/B) ratio (p = 0.049) of gut microbiome. However, no significant influences are observed on fecal TMA content, circulating TMAO levels, or TMA-producing gene clusters, including choline TMA-lyase (CutC/D), carnitine monooxygenase (CntA/B), and betaine reductase (GrdH). CONCLUSIONS: Intervention with 10 g day-1 of ITFs for 3 months is not sufficient to reduce plasma TMAO levels in peritoneal dialysis patients, but it improves the gut microbiome composition.


Assuntos
Inulina , Diálise Peritoneal , Humanos , Inulina/farmacologia , Frutanos , Estudos Cross-Over , Metilaminas , Colina
16.
Opt Express ; 31(26): 43125-43134, 2023 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-38178414

RESUMO

We demonstrate a single-stage all-fiber nanosecond amplifier with a total average power of greater than 1.4 kW by employing what we believe to be a novel multi-cavity passively Q-switched fiber laser as the seed laser. The multi-cavity seed laser adopts a piece of Yb-doped fiber (YDF) as saturable absorber (SA), and it includes two external cavities resonating at 1030 nm and an internal cavity working at 1064 nm, respectively. Using such a scheme, a stable dual-channel laser output with a total average power of >35 W, a pulse width of 45 ns, and an optical conversion efficiency of 72% operating at 1064 nm is achieved. By power scaling the multi-cavity seed laser, a dual-channel single-stage nanosecond amplifier is obtained with a single-port average power of exceeding 700 W and a pulse energy of about 7.3 mJ. To the best of our knowledge, this work is the highest average power and optical conversion efficiency for passively Q-switched all-fiber laser employing SA fiber, and the highest average power for a single-stage all-fiber nanosecond amplifier.

17.
Front Neurosci ; 16: 1080066, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36507320

RESUMO

Introduction: Secondhand smoke (SHS) is common in older adults; however, its cognitive effect is unclear. We aimed to examine the association between serum cotinine level and cognitive functioning among non-smoking older adults. Materials and methods: A total of 2,703 older adults aged 60 and above from the National Health and Nutrition Examination (NHANES) Survey 2011-2014 were included. Serum cotinine level was analyzed in the laboratory. A level ≤10 ng/ml and a response of "no" to the question "Do you currently smoke?" were used to select non-smokers. Cognitive functioning was measured using the Consortium to Establish a Registry for Alzheimer's disease Word Learning subtest (CERAD-WL) immediate and delayed recall tests, the Animal Fluency test (AFT), and the Digit Symbol Substitution test (DSST). Multivariable linear regression models were constructed to examine the association between serum cotinine level quartile and test-specific and global cognition z scores adjusting for age, race/ethnicity, education, depressive symptoms, body mass index, alcohol use, smoking history, prevalent coronary heart disease (CHD), stroke, and systolic blood pressure. Results: About half of the participants (mean age 70.5 years) were female (53.6%), non-Hispanic White (48.3%), and completed some college and above (50.2%). Multivariate linear regressions with a reference group being those in the 1st quantile (lowest) showed that participants in the 4th quartile (highest) of serum cotinine level had lower immediate recall [ß = -0.16, 95% confidence interval (CI) = -0.29, -0.03], AFT (ß = -0.19, 95% CI = -0.33, -0.05), DSST (ß = -0.27, 95% CI = -0.39, -0.15), and global cognition (ß = -0.26, 95% CI = -0.39, -0.14) z scores. Participants in the 3rd quartile had lower immediate recall (ß = -0.16, 95% CI = -0.30, -0.02) and global cognition (ß = -0.16, 95% CI = -0.29, -0.02) z scores. Participants in the 2nd quartile had lower delayed recall z scores (ß = -0.16, 95% CI = -0.29, -0.02). Conclusion: Higher serum cotinine level was associated with worse cognitive functioning in non-smoking older adults. Prevention and reduction of SHS in older adults may help protect their cognitive functioning.

18.
Curr Med Sci ; 42(5): 981-990, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35896932

RESUMO

OBJECTIVE: Epidemiology studies indicate that green tea polyphenols (GTP) perform a protective effect on cardiovascular diseases, but the underlying mechanisms are complex. The present study aimed to investigate the effect of GTP on high-fat diets (HFD) induced-early vascular aging. METHODS: Six-week young adult Wistar rats were fed with standard chow or HFD in the presence and absence of GTP (200 mg/kg body weight) for 18 weeks. In vitro experiment, human umbilical vascular endothelial cells (HUVECs) were treated with palmitic acid (PA) and GTP. RESULTS: The results showed that GTP alleviated the disorganized arterial wall and the increased intima-media thickness induced by HFD. In addition, the vascular oxidative injury was suppressed following GTP treatment. Furthermore, GTP elevated the ratio of LC3-II/LC3-I and suppressed expression of p62/SQSTM1, and restored SIRT3 expression in the aorta of HFD rats. Consistently, in cultured HUVECs, GTP inhibited cell senescence indicated by SA-ß-gal and promoted endothelial autophagy compared with the PA treatment group. The activity of SIRT3 was specifically inhibited by 3-TYP, and the protective effect of GTP was consequently abolished. CONCLUSION: The findings indicated that GTP protected against early vascular senescence in young HFD rats via ameliorating oxidative injury and promoting autophagy which was partially regulated by the SIRT3 pathway.


Assuntos
Dieta Hiperlipídica , Sirtuína 3 , Animais , Ratos , Envelhecimento , Antioxidantes/farmacologia , Autofagia , Espessura Intima-Media Carotídea , Dieta Hiperlipídica/efeitos adversos , Células Endoteliais/metabolismo , Guanosina Trifosfato/farmacologia , Ácido Palmítico/farmacologia , Polifenóis/farmacologia , Ratos Wistar , Proteína Sequestossoma-1/metabolismo , Sirtuína 3/metabolismo , Sirtuína 3/farmacologia , Chá/metabolismo
19.
Light Sci Appl ; 11(1): 181, 2022 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-35701403

RESUMO

We discover that the spatially coherent radiation within a certain frequency range can be obtained without a common nonlinear optical process. Conventionally, the emission spectra were obtained by de-exciting excited centers from real excited energy levels to the ground state. Our findings are achieved by deploying a high-entropy glass system (HEGS) doped with neodymium ions. The HEGS exhibits a much broader infrared absorption than common glass systems, which can be attributed to be high-frequency optical branch phonons or allowable multi-phonon processes caused by phonon broadening in the system. A broadened phonon-assisted wideband radiation (BPAWR) is induced if the pump laser is absorbed by the system. The subsequent low-threshold self-absorption coherence modulation (SACM) can be controlled by changing excitation wavelengths, sample size, and doping concentrations. The SACM can be red-shifted through the emission of phonons of the excited species and be blue-shifted by absorbing phonons before they are de-excited. There is a time delay up to 1.66 ns between the pump pulse and the BPAWR when measured after traveling through a 35 mm long sample, which is much longer than the Raman process. The BPAWR-SACM can amplify the centered non-absorption band with a gain up to 26.02 dB. These results reveal that the shift of the novel radiation is determined by the frequency of the non-absorption band near the absorption region, and therefore the emission shifts can be modulated by changing the absorption spectrum. When used in fiber lasers, the BPAWR-SACM process may help to achieve tunability.

20.
Opt Express ; 30(4): 5700-5708, 2022 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-35209526

RESUMO

We demonstrate the generation of high-energy (133 mJ) and sub-nanosecond (∼270 ps) deep ultraviolet (DUV) pulses at 266 nm by sum-frequency mixing in LiB3O5 (LBO) crystals. The highest 133 mJ pulse energy ever reported corresponds to a peak power of 0.49 GW and an energy conversion efficiency of 13.3% from the infrared at 1064 nm to DUV at 266 nm. This is the highest output energy ever reported for the DUV sub-nanosecond pulses to the best of our knowledge. Higher energy efficiency of 25.7% can be achieved from 1064 nm to 266 nm when the fundamental energy was reduced to 346 mJ. Furthermore, the DUV generations using LBO and typical ß-BaB2O4 (BBO) crystals were compared regarding the energy efficiency, and the effects of the nonlinear absorption are discussed.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA