Search

Nonlinear photonics has unveiled new avenues for applications in metrology, spectroscopy, and optical communications. Recently, there has been a surge of interest in integrated platforms, attributed to their fundamental benefits, including compatibility with complementary metal-oxide semiconductor (CMOS) processes, reduced power consumption, compactness, and cost-effectiveness. This paper provides a comprehensive review of the key nonlinear effects and material properties utilized in integrated platforms. It discusses the applications and significant achievements in supercontinuum generation, a key nonlinear phenomenon. Additionally, the evolution of chip-based optical frequency combs is reviewed, highlighting recent pivotal works across four main categories. The paper also examines the recent advances in on-chip switching, computing, signal processing, microwave generation, and quantum applications. Finally, it provides perspectives on the development and challenges of nonlinear photonics in integrated platforms, offering insights into future directions for this rapidly evolving field.

In agricultural production, it is crucial to increase the availability of phosphorus (P) in cultivated soil to solve the P limitation. Arbuscular mycorrhizal fungi (AMF) have been proven to promote crop nutrient absorption effectively, while biochar can lead to improvements in soil properties. However, the possible synergistic effect of AMF and biochar on P uptake by crops as well as its underlying mechanisms are unclear. In this study, we conducted a pot experiment to explore the effects of biochar and AMF (Glomus etunicatum) on the community of rhizospheric phosphate-solubilizing microorganisms (PSMs) of maize (Zea mays L. Xianyu-335) using metagenomic methods. The experiment used 0 mg P2O5 g·kg−1 soil (P0) and 30 mg P2O5 g·kg−1 soil (P30) application rates. Each P application rate included 0 (NC), 20 g·kg−1 biochar (BC) addition, inoculation AMF, and without AMF treatments (NM) for a total of eight treatments. During the experiment, both the P uptake and the biomass of maize were measured. The study found that the combination of AMF and biochar significantly increased the mycorrhizal colonization rate of maize roots, regardless of P application level. It was observed that the P uptake by maize was significantly increased when exposed to a combination of AMF and biochar. The increase in P uptake in P0 treatments was 67% higher than the sum of the effects of biochar and AMF inoculation alone. The increase was only 35% higher in P30 treatments, demonstrating a substantially higher interactive effect under P0 than under P30 conditions. The AM-BC treatments significantly increased the abundance of Streptomyces, Bacillus, and Pseudomonas, genera that are known to contain PSMs. In addition, the abundance of genes related to P-cycling (gcd, phoD, and ugpQ) in PSMs increased significantly by 1.5–1.8 times in AM-BC treatments compared with NM-BC and AM-NC treatments under P0 conditions. This increase was significantly and positively correlated with the P uptake. Overall, the results suggest that biochar can help AMF colonize the roots, increasing the functional roles of PSMs in the rhizosphere, which in turn promotes P uptake and biomass in maize. This study provides a new way to improve P-use efficiency and reduce the need for P-fertilizer application in agricultural production. [ABSTRACT FROM AUTHOR]

We design a graded-index ring-core fiber with a GeO2-doped silica ring core and SiO2 cladding. This fiber structure can inhibit the effect of spin-orbit coupling to mitigate the power transfer among different modes and eventually enhance the orbital angular momentum (OAM) mode purity. By changing the high-index ring core from the step-index to parabolic graded-index profile, the purity of the OAM1,1 mode can be improved from 86.48% to 94.43%, up by 7.95%. The proposed fiber features a flexible structure, which can meet different requirements for mode order, effective mode area, etc. Simulation results illustrate that the parabolic-index ring-core fiber is promising in enhancing the OAM mode purity, which could potentially reduce the channel crosstalk in mode-division-multiplexed optical communication systems. [ABSTRACT FROM AUTHOR]

Supercontinuum (SC) has opened up possibilities for numerous applications in optical communications, signal processing, metrology, and spectroscopy. Supercontinuum generation (SCG) in the integrated nonlinear platforms has attracted much interest recently, due to its fundamental advantages in terms of complementary metal oxide semiconductor compatibility, low power consumption, compact size, and cost‐effectiveness. In this paper, the latest progress on various types of nanophotonic waveguides for SCG is reviewed. The material properties of silicon, germanium, silicon–germanium alloy, silicon nitride, silica, chalcogenide, III–V materials, lithium niobate, and other materials, which are used as nonlinear media for SCG are discussed. The wavelength‐dependent nonlinear Kerr index, material, and nonlinear loss of the waveguides are taken into account. This review mainly focuses on the SCG resulting from the cubic χ(3) nonlinearity processes pumped by the femtosecond pulse. The recent representative SCG works based on the integrated optical waveguides are summarized, and further classified according to the dispersion characteristics. Furthermore, different types of spectra broadening mechanisms in details according to the classifications are analyzed. Perspectives on the SC spectral coverage, the realization of various dispersion curves, and the novel materials, which are the key aspects of the SCG in nanophotonic waveguides are provided. [ABSTRACT FROM AUTHOR]

The high consumption and emission of sulfonamide antibiotics (SAs) have a considerable threat to humans and ecosystems, so there is a need to develop safer and more effective methods than conventional strategies for the optimal removal of these compounds. In this study, four SAs with different substituents, sulfadiazine (SDZ), sulfamerazine (SMR), sulfamethoxazole (SMX), and sulfamethazine (SMZ) were removed by a pure culture of Paenarthrobacter ureafaciens YL1. The effect of the initial SAs concentration on the growth rate of strain YL1 was investigated. The results showed that the strain YL1 effectively removed various SAs in the concentration range of 0.05–2.4 mmol·L−1. The Haldane model was used to perform simulations of the experimental data, and the regression coefficient of the model indicated that the model had a good predictive ability. During SAs degradation, the maximum specific growth rate of strain YL1 was ranked as SMX > SDZ > SMR > SMZ with constants of 0.311, 0.304, 0.302, and 0.285 h−1, respectively. In addition, the biodegradation of sulfamethoxazole (SMX) with a five-membered substituent was the fastest, while the six-membered substituent of SMZ was the slowest based on the parameters of the kinetic equation. Also, density functional theory (DFT) calculations such as frontier molecular orbitals (FMOs), and molecular electrostatic potential map analysis were performed. It was evidenced that different substituents in SAs can affect the molecular orbital distribution and their stability, which led to the differences in the growth rate of strain YL1 and the degradation rate of SAs. Furthermore, the toxicity of P. ureafaciens is one of the crucial factors affecting the biodegradation rate: the more toxic the substrate and the degradation product are, the slower the microorganism grows. This study provides a theoretical basis for effective bioremediation using microorganisms in SAs-contaminated environments. [ABSTRACT FROM AUTHOR]

In this paper, we design a silica-cladded Germania-doped ring-core fiber (RCF) that supports orbital angular momentum (OAM) modes. By optimizing the fiber structure parameters, the RCF possesses a near-zero flat dispersion with a total variation of <±30 ps/nm/km over 1770 nm bandwidth from 1040 to 2810 nm for the OAM1,1 mode. A beyond-two-octave supercontinuum spectrum of the OAM1,1 mode is generated numerically by launching a 40 fs 120 kW pulse train centered at 1400 nm into a 12 cm long designed 50 mol% Ge-doped fiber, which covers 2130 nm bandwidth from 630 nm to 2760 nm at −40 dB of power level. This design can serve as an efficient way to extend the spectral coverage of beams carrying OAM modes for various applications. [ABSTRACT FROM AUTHOR]

Orbital angular momentum (OAM) multiplexing technology is expected as one of the prospective candidates for sustaining the further increment of data-transmission capacity in the optical communication systems. Advanced multiplexing technology of combining OAM-based mode division multiplexing (MDM) in the multicore fiber (MCF) with wavelength division multiplexing (WDM) can further improve the transmission rate and spectrum efficiency in the communication systems. In this paper, a multi-ring-air-core fiber (MRACF) supporting thousands of OAM modes is designed and analyzed. The tradeoffs between ring number/density and their corresponding system performance parameters in this fiber are systematically investigated. Based on the analytical results, MRACF with 37 rings can support a record high 4440 radially fundamental OAM modes at 1550 nm, featuring <−53 dB inter-ring crosstalk and >5.67 × 10−4 intra-ring modal effective refractive index difference. Furthermore, a record-high 4144 radially fundamental OAM modes with <−40 dB inter-ring crosstalk can be supported across C and L bands from 1530 nm to 1625 nm, which is one order of magnitude larger than the number of linearly polarized (LP) modes or supermodes ever reported within one single fiber. [ABSTRACT FROM AUTHOR]

Sulfamethoxazole (SMX) is a widespread and persistent pollutant in the environment. Although the screening and analysis of SMX-degrading bacteria have been documented, the interaction mechanisms of functional microorganisms are still poorly understood. This study constructed a consortium with strain YL1 and YL2 supplied with SMX as the sole carbon and energy source. The coexisting mechanism and the removal of SMX of the consortium were investigated. The total oxidizable carbon (TOC) removal rate of the combined bacterial system was 38.94% compared to 29.45% for the single bacterial system at the same biomass. The mixed bacterial consortium was able to resist SMX at concentrations up to 400 mg/L and maintained a stable microbial structure at different culture conditions. The optimum conditions found for SMX degradation were 30 °C, pH 7.0, a shaking speed of 160 r·min−1, and an initial SMX concentration of 200 mg·L−1. The degradation of SMX was accelerated by the addition of YL2 for its ability to metabolize the key intermediate, 4-aminophenol. The removal rate of 4-aminophenol by strain YL2 reached 19.54% after 5 days. Genome analysis revealed that adding riboflavin and enhancing the reducing capacity might contribute to the degradation of SMX. These results indicated that it is important for the bioremediation of antibiotic-contaminated aquatic systems to understand the metabolism of bacterial communities. [ABSTRACT FROM AUTHOR]

Introduction: On April 1, 2017, California Proposition 56 (Prop 56) was implemented, increasing the excise tax on cigarettes by $2/pack. This study compares the association of Prop 56 with smoking prevalence and smoking intensity across racial/ethnic groups, further examining distinctions across income subgroups within each racial/ethnic group.Aims and Methods: The study used pooled cross-sectional data from the 2012-2018 California Behavioral Risk Factor Surveillance System. We examined two outcomes: current smoking prevalence and smoking intensity conditional on current smoking. A two-part econometric model was used to estimate the association of Prop 56 with smoking prevalence and intensity using multiple logistic regression and multiple linear regression, respectively. The two-part model was run separately for all adults (full sample) and each racial/ethnic group. Within each racial/ethnic group, we ran stratified analyses by income subgroups.Results: The results indicated that Prop 56 was negatively associated with smoking prevalence among full sample, Hispanic, White, and African American adults and negatively associated with smoking intensity among full sample and White smokers. Stratified analyses by race/ethnicity and income showed that Prop 56 was negatively associated with smoking prevalence among low-income full sample and White adults and among middle-income smokers in the full, Hispanic, White, African American, and Asian samples. Prop 56 was negatively associated with smoking intensity among middle-income Hispanic and high-income White smokers. The association between Prop 56 and smoking intensity was positive among high-income African American smokers.Conclusion: Prop 56 was associated with a reduction in smoking prevalence across multiple racial/ethnic groups, particularly within the low- and middle-income subgroups.Implications: Our findings indicate that the reduction in smoking prevalence immediately following the implementation of Prop 56 tobacco tax increase was significant across a variety racial/ethnic groups, particularly low- and middle-income subgroups. We found differential responses in smoking prevalence across income groups among Whites but not among racial/ethnic minorities. We found no evidence of any significance association between Proposition 56 and smoking intensity among minorities and economically vulnerable populations, except for middle-income Hispanics. Researchers, policy makers, and advocates should consider the additional merits of targeted, community-based, noneconomic tobacco control interventions in reaching low- and middle-income groups within racial/ethnic minorities. [ABSTRACT FROM AUTHOR]

Background and aims: Non‐Hispanic African Americans (African Americans) smoke fewer cigarettes per day (CPD) and are more likely to be non‐daily smokers than non‐Hispanic whites (whites). Little is known about how changes in cigarette prices might contribute to these differences. This study aimed to measure the price‐responsiveness of smoking participation, non‐daily smoking among current smokers and smoking intensity among daily or non‐daily smokers for African Americans and compare the price‐responsiveness estimates with those for whites. Design Analysis of data from the 2009–14 National Adult Tobacco Surveys and cigarette price data from the Tax Burden on Tobacco report. Setting: United States. Participants: A total of 19 232 African American and 197 939 white adults aged 18+. Measurements We used a three‐part econometric model of cigarette demand to estimate the price‐responsiveness of smoking participation, daily versus non‐daily smoking and smoking intensity. The model controlled for secular variation, state‐level anti‐smoking sentiment and smoke‐free air laws and socio‐demographics. Findings In 2009–14, 20.2% of African Americans and 17.7% of whites identified as current smokers; 70.2% of African American smokers and 81.4% of white smokers smoked daily. The price elasticity of smoking participation was significant for whites at −0.16 [95% confidence interval (CI) = –0.23, –0.09], indicating that a 10% increase in prices would reduce smoking participation by 1.6%, but not statistically significant for African Americans, and this racial/ethnic differential price responsiveness was not statistically significant. The price elasticity of smoking intensity was statistically significant for African American daily smokers at −0.29 (95% CI = −0.42, –0.16), but not statistically significant for white daily smokers, and this racial/ethnic differential price‐responsiveness was statistically significant. The price elasticity of daily versus non‐daily smoking among current smokers, and the price elasticity of smoking intensity among non‐daily smokers were not statistically significant for either racial/ethnic group. Conclusion: In the United States, cigarette price increases may have stronger effects on decreasing daily smokers' consumption among African Americans than among non‐Hispanic whites. [ABSTRACT FROM AUTHOR]

Introduction: To study the association between health care utilization and menthol cigarette use and whether the association differed between African American (AA) and non-AA smokers.Methods: We analyzed the three most recent 2005, 2010, and 2015 National Health Interview Survey Cancer Control Supplements. After incorporating propensity score weights adjusting for observed differences between menthol and non-menthol users, we estimated Zero-Inflated Poisson models on hospital nights, emergency department visits, doctor visits, and home visits as a function of menthol use status and other covariates separately for current cigarette smokers and recent quitters (former smokers quitting cigarette smoking ≤ 4 years).Results: Although current menthol smokers smoked fewer cigarettes per day than current non-menthol smokers, they did not differ from current non-menthol smokers in health care utilization. Among recent quitters, those who used to smoke menthol cigarettes had higher odds of having hospital nights than those who used to smoke non-menthol cigarettes. However, we did not find any significant association between menthol use and other health care utilization-emergency department visits, doctor visits, and home visits-among recent quitters. Moreover, compared with non-AA recent quitters, AA recent quitters had higher odds of having home visits, but fewer home visits, if they used to smoke menthol cigarettes.Conclusion: Menthol use was associated with greater hospitalization among recent quitters, and the association between home visits and menthol use differed between AA and non-AA recent quitters.Implications: This is the first study that used econometric models to study the association between health care utilization and menthol cigarette use and examine whether the association differed between AA and non-AA smokers. Our study found health care utilization did not differ by menthol use status for current smokers, although current menthol smokers smoked fewer cigarettes per day than current non-menthol smokers. However, we found menthol use was associated with higher odds of having hospital nights for recent quitters. We also found AA recent quitters had a different association between home visits and menthol use compared with non-AA recent quitters. [ABSTRACT FROM AUTHOR]

In this work, we propose and design a highly dispersive coupled ring-core fiber (CRF) with two concentric high-index rings using Schott glass for orbital angular momentum (OAM) modes. By properly selecting the fiber geometrical parameters, the OAM130,1 mode supported in the proposed CRF has a large negative chromatic dispersion (CD) of −20 271 ps/(nm km) at 1260.4 nm. We also show that the proposed CRF could be an excellent candidate for various CD-related applications of OAM modes in the optical fiber. The dispersion of the OAM3,1 mode can reach down to −75 273 ps/(nm km) at 1491 nm. Furthermore, the effect of the geometrical parameters on chromatic dispersion for different OAM modes is investigated. Adjusting the parameters of the inner ring or the outer ring could greatly influence the peak value of the dispersion, while moving the two high-index rings at the same time mainly changes the position of the crossing wavelength. [ABSTRACT FROM AUTHOR]

Objectives. To compare the association of California Proposition 56 (Prop 56), which increased the cigarette tax by $2 per pack beginning on April 1, 2017, with smoking behavior among low- and high-income adults. Methods. Drawing on a sample of 17 206 low-income and 21 324 high-income adults aged 21 years or older from the 2012 to 2018 California Behavioral Risk Factor Surveillance System data, we explored 2 outcomes: current smoking prevalence and smoking intensity (average number of cigarettes per day among current smokers). For each income group, we estimated a multivariable logistic regression to analyze the association of Prop 56 with smoking prevalence and a multivariable linear regression to analyze the association of Prop 56 with smoking intensity. Results. Although we observed no association between smoking intensity and Prop 56, we found a statistically significant decline in smoking prevalence among low-income adults following Prop 56. No such association was found among the high-income group. Conclusions. Given that low-income Californians smoke cigarettes at greater rates than those with higher incomes, our results provide evidence that Prop 56 is likely to reduce income disparities in cigarette smoking in California. [ABSTRACT FROM AUTHOR]

Introduction: The proportion of smokers who do not smoke daily has increased over time, but nondaily smokers are a heterogeneous group. We compare characteristics and other tobacco product use of infrequent nondaily, frequent nondaily, and daily US adult smokers.Methods: We analyzed data from the 1998, 2000, 2005, and 2010 National Health Interview Surveys. Current smokers were categorized as daily, infrequent nondaily (smoked 1-12 days in the past 30 days), and frequent nondaily (smoked 13-29 days in the past 30 days) smokers. Multinomial logistic regression analysis was used to analyze the correlates of infrequent nondaily, frequent nondaily, and daily smoking.Results: Among current smokers, 8.3% were infrequent nondaily, 8.1% were frequent nondaily, and 83.6% were daily smokers. The prevalence of infrequent versus daily smoking increased over time, with a smaller increase among non-Hispanic Blacks than non-Hispanic Whites. The adjusted odds of both infrequent and frequent smoking versus daily smoking differed by age, race/ethnicity, education, poverty status, marital status, region, quit attempts in the past 12 months, and binge drinking. Snuff users (vs. non-snuff users) were 2.4 times as likely to be infrequent than daily smokers. There were also differences in race/ethnicity, education, marital status, region, quit attempts, and snuff use between infrequent versus frequent smokers.Conclusion: Infrequent smokers differ from both frequent and daily smokers in socio-demographics, quit attempts, and snuff use. The heterogeneity of nondaily smokers should be considered in developing targeted tobacco control and smoking cessation programs.Implications: Infrequent and frequent nondaily smokers were found to differ from daily smokers in age, race/ethnicity, education, poverty status, marital status, region, and quit attempts and they were different from each other in race/ethnicity, education, marital status, region, and quit attempts. Binge drinkers were more likely to be infrequent smokers and frequent smokers versus daily smokers. Current snuff users were found to have increased odds of infrequent smoking versus daily smoking and versus frequent smoking. These results highlight the importance of acknowledging the differences among nondaily smokers in smoking frequency in developing targeted tobacco control and smoking cessation programs. [ABSTRACT FROM AUTHOR]

Objective: To examine the relationship between spending on electronic cigarettes (e-cigarettes) and disease symptoms compared with the relationship between 30-day e-cigarette use and disease symptoms among adult cigarette smokers in the U.S. Methods: We analyzed data from the Tobacco and Attitudes Beliefs Survey which included 533 respondents aged 24+ who were current cigarette smokers and e-cigarette ever users. Fifteen self-reported disease symptoms were included as outcome variables. Separate multivariable logistic regression models were estimated for each disease symptom with total spending on e-cigarettes in the past 30 days and with reported 30-day e-cigarette use. All models controlled for cigarettes smoked per day (CPD) and sociodemographic characteristics. Results: We found that those who spent more on e-cigarettes were more likely to report chest pain (AOR = 1.25, 95% CI 1.02–1.52), to notice blood when brushing their teeth (AOR = 1.23, 95% CI 1.02–1.49), to have sores or ulcers in their mouth (AOR = 1.36, 95% CI 1.08–1.72), and to have more than one cold (AOR = 1.36, 95% CI 1.05–1.78) than those with no spending on e-cigarettes in the past 30 days in an adjusted analysis. After controlling for CPD and other covariates, there were no significant relationships between 30-day e-cigarette use and symptoms. Even after controlling for CPD, e-cigarette expenditures or use was associated with greater odds of wheezing and shortness of breath. Conclusions: E-cigarette expenditures might be a more useful measure of intensity of e-cigarette use. The additional health effect of e-cigarette use or expenditures among smokers independent of the effect of CPD suggests that e-cigarette use adds adverse health effects even among cigarette smokers. [ABSTRACT FROM AUTHOR]

Aims To examine the transitions in smoking status among non-daily smokers who transitioned to daily or former smokers or remained as non-daily smokers during a 12-month period. We analyzed factors associated with these transitions, including the use of cigars and smokeless tobacco (SLT). Design Secondary data analyses using pooled data from the 2003, 2006/07 and 2010/11 Tobacco Use Supplements to the Current Population Survey (TUS-CPS). Setting United States. Participants Self-respondents aged 18+ who have smoked for more than 5 years and were non-daily smokers 12 months before the interview ( n = 13 673, or 14.5% of current smokers). Measurements Multinomial logistic regression model to determine the correlates of non-daily to daily, stable non-daily and non-daily to former smoking transitions among non-daily smokers at baseline. The model controlled for socio-demographic factors and the use of cigars and SLT. Findings Of the adults in our sample, 2.6% were non-daily smokers at baseline. Among these, 69.7% remained non-daily smokers (stable non-daily smokers), 18.4% became daily smokers (non-daily to daily smokers) and 11.9% quit smoking (non-daily to former smokers) after 12 months. The non-daily to daily versus stable non-daily smoking transition was less likely among those who were aged 65+ ( P = 0.018), male ( P < 0.001), Hispanic ( P < 0.001), with an income of $25 000-49 999 or ≥$75 000 and current users of SLT ( P = 0.003), but more likely among those without a college degree compared with the appropriate reference group. The non-daily to former versus stable non-daily smoking transition was less likely among those aged 25+, male ( P = 0.013), non-Hispanic Asian ( P = 0.032), without a college degree, widowed/divorced/separated ( P = 0.013) or never married ( P = 0.011) and current users of cigars ( P = 0.003) compared with the appropriate reference group. Conclusions While more than two-thirds of non-daily smokers in the United States remain as such after 12 months, others become daily smokers or quit. The likelihood of remaining stable non-daily smokers and of transition from non-daily to daily and non-daily to former smokers is associated with socio-demographic factors and current use of cigars and smokeless tobacco. [ABSTRACT FROM AUTHOR]

Introduction: Tobacco use prevalence has been commonly estimated on a product by product basis and the extent of polytobacco use among current users of each tobacco product is not well understood. This study aimed to examine the prevalence, trends, and correlates of polytobacco use among current users of cigarettes, cigars, chewing tobacco, and snuff in US adults aged ≥18.Methods: We used pooled data from the 1998, 2000, 2005, and 2010 Cancer Control Supplements of the National Health Interview Survey (N = 123 399 adults). Multivariate logistic regression models were estimated to determine significant factors associated with polytobacco use.Results: In 2010, the prevalence of polytobacco use was 8.6% among current cigarette smokers, 50.3% among current cigar users, 54.8% among current chewing tobacco users, and 42.5% among current snuff users. After controlling for other covariates, gender and race/ethnicity did not show consistent associations with poly-use across these four groups of current tobacco users; however, a positive association of young adulthood, less than high school education, and binge drinking with poly-use was consistently found among all these groups.Conclusions: Polytobacco use is extremely popular among current users of non-cigarette tobacco products. Polytobacco use patterns differ across sociodemographic subpopulations, and the gender and racial/ethnic profiles in poly-users vary across different groups of current tobacco users. Tobacco control strategies need to consider the interrelationships in the use of different tobacco products and the diverse profiles of poly-users in order to develop tailored tobacco prevention and intervention policies to further reduce the burden of tobacco use. [ABSTRACT FROM AUTHOR]

This paper proposes a new model to identify if and how much the educational attainment gap between blacks and whites is due to the difference in their neighborhoods. In this model, individuals belong to two unobserved types: the endogenous type, which may move in response to the neighborhood effect on their education; or the exogenous type, which may move for reasons unrelated to education. The Heckman sample selection model becomes a special case of the current model in which the probability of one type of individuals is zero. Although we cannot find any significant neighborhood effect in the usual Heckman sample selection model, we do find heterogeneous effects in our two-type model. In particular, there is a substantial neighborhood effect for the movers who belong to the endogenous type. No significant effects exist for other groups. We also find that the endogenous type has more education and moves more often than the exogenous type. On average, we find that the neighborhood variable, the percentage of high school graduates in the neighborhood, accounts for about 28.96% of the education gap between blacks and whites. [ABSTRACT FROM AUTHOR]

Biodegradation of 1,4-dioxane (dioxane) contamination has gained much attention for decades. In our previous work, we isolated a highly efficient dioxane degrader, Xanthobacter sp. YN2, but the underlying mechanisms of its extraordinary degradation performance remained unresolved. In this study, we performed a comparative transcriptome analysis of YN2 grown on dioxane and citrate to elucidate its genetic degradation mechanism and investigated the transcriptomes of different dioxane degradation stages (T0, T24, T48). We also analyzed the transcriptional response of YN2 over time during which the carbon source switched from citrate to dioxane. The results indicate that strain YN2 was a methylotroph, which provides YN2 a major advantage as a pollutant degrader. A large number of genes involved in dioxane metabolism were constitutively expressed prior to dioxane exposure. Multiple genes related to the catabolism of each intermediate were upregulated by treatment in response to dioxane. Glyoxylate metabolism was essential during dioxane degradation by YN2, and the key intermediate glyoxylate was metabolized through three routes: glyoxylate carboligase pathway, malate synthase pathway, and anaplerotic ethylmalonyl–CoA pathway. Genes related to quorum sensing and transporters were significantly upregulated during the early stages of degradation (T0, T24) prior to dioxane depletion, while the expression of genes encoding two-component systems was significantly increased at late degradation stages (T48) when total organic carbon in the culture was exhausted. This study is the first to report the participation of genes encoding glyoxalase, as well as methylotrophic genes xoxF and mox, in dioxane metabolism. The present study reveals multiple genetic and transcriptional strategies used by YN2 to rapidly increase biomass during growth on dioxane, achieve high degradation efficiency and tolerance, and adapt to dioxane exposure quickly, which provides useful information regarding the molecular basis for efficient dioxane biodegradation. [ABSTRACT FROM AUTHOR]

Performing pattern recognition via correlation in the optical domain has potential advantages, including: (i) high-speed operation at the line rate and (ii) tunability and scalability by operating on the optical wave properties. Such pattern recognition might be performed on quadrature-phase-shift-keying (QPSK) data transmitted over an optical network, which generally requires using coherent detection to distinguish the phase levels of the correlator output. To enable simpler detection, we combine optical correlation with optical biasing to experimentally demonstrate tunable and scalable QPSK pattern recognition using direct detection. The pattern is applied by adjusting the relative phases of the local pumps. Delayed QPSK signals, a coherent bias tone, and local pumps undergo nonlinear wave-mixing in a periodically poled lithium niobate (PPLN) waveguide to perform optical correlation and biasing. The biased correlator output is captured using direct detection, where the highest power level corresponds only to the pattern. Multiple QPSK pattern recognitions are achieved error-free over 3072 symbols using power thresholding values of (i) 0.78 at a 5-Gbaud rate and 0.73 at a 10-Gbaud rate for 2-symbol pattern recognition and (ii) 0.81 at a 5-Gbaud rate and 0.79 at a 10-Gbaud rate for 3-symbol pattern recognition.

In this paper, we experimentally demonstrate an 8-Gbit/s quadrature-phase-shift-keying (QPSK) coherent underwater wireless optical communication (UWOC) link under scattering conditions at 532 nm. At the transmitter, we generate the 532-nm QPSK signal using second-harmonic generation (SHG), where the 1064-nm signal modulated with four phase levels of an 8-phase-shift-keying (8-PSK) format is phase doubled to produce the 532-nm QPSK signal. To enhance the receiver sensitivity, we utilize a local oscillator (LO) at the receiver from an independent laser source. The received QPSK data beam is mixed with the independent LO for coherent heterodyne detection. Results show that the bit error rates (BERs) of the received QPSK signal can reach below the 7% forward error correction (FEC) limit under turbid water with attenuation lengths (γL) up to 7.4 and 6.1 for 2- and 8-Gbit/s QPSK, respectively. The corresponding receiver sensitivities are -34.0 and -28.4 dBm for 2- and 8-Gbit/s QPSK, respectively.

In general, space-time wave packets with correlations between transverse spatial fields and temporal frequency spectra can lead to unique spatiotemporal dynamics, thus enabling control of the instantaneous light properties. However, spatiotemporal dynamics generated in previous approaches manifest themselves at a given propagation distance yet are not arbitrarily tailored longitudinally. Here, we propose and demonstrate a new versatile class of judiciously synthesized wave packets whose spatiotemporal evolution can be arbitrarily engineered to take place at various predesigned distances along the longitudinal propagation path. Spatiotemporal synthesis is achieved by introducing a 2-dimensional spectrum comprising both temporal and longitudinal wavenumbers associated with specific transverse Bessel-Gaussian fields. The resulting spectra are then employed to produce wave packets evolving in both time and axial distance - in full accord with the theoretical analysis. In this respect, various light degrees of freedom can be independently manipulated, such as intensity, polarization, and transverse spatial distribution (e.g., orbital angular momentum). Through a temporal-longitudinal frequency comb spectrum, we simulate the synthesis of the aforementioned wave packet properties, indicating a decrease in relative error compared to the desired phenomena as more spectral components are incorporated. Additionally, we experimentally demonstrate tailorable spatiotemporal fields carrying time- and longitudinal-varying orbital angular momentum, such that the local topological charge evolves every ∼1 ps in the time domain and 10 cm axially. We believe our space-time wave packets can significantly expand the exploration of spatiotemporal dynamics in the longitudinal dimension. Such wave packets might potentially enable novel applications in light-matter interactions and nonlinear optics.

Aims: To examine the relationship between changes in electronic cigarette (e-cigarette) use and subsequent cigarette smoking cessation., Methods: Using data from the Population Assessment of Tobacco and Health Study (wave 1-wave 4), we analysed a study cohort of 3014 current adult cigarette smokers at wave 1 who tried to quit during the past 12 months. We categorised changes in e-cigarette use from wave 1 to wave 2 as: daily initiation, non-daily initiation, increase to daily use, increase to non-daily use, stable daily use, stable non-daily use, decrease from daily use, quit non-daily use and non-use. We estimated multivariable logistic regressions on short-term (≥1 month and <12 months) cigarette smoking cessation at wave 3 and long-term (≥12 months) cigarette smoking cessation at wave 4. We conducted sensitivity analyses using alternative study cohorts., Results: Among the study cohort, 2.4% initiated daily, 7.5% initiated non-daily, 1.0% increased to daily, 1.4% increased to non-daily, 1.5% maintained daily, 3.0% maintained non-daily, 2.4% decreased from daily and 3.8% quit non-daily e-cigarette use between waves 1 and 2; 7.9% and 6.9% reported short-term and long-term cigarette smoking cessation. 15.1% of short-term and 16.3% of long-term cigarette quitters used e-cigarettes. Compared with non-users, smokers who initiated daily, increased to daily or quit non-daily e-cigarette use between waves 1 and 2 had higher odds of short-term cigarette smoking cessation at wave 3. These results are robust to different study cohort specifications., Conclusion: The findings suggest a complex relationship between changes in e-cigarette use and subsequent cigarette smoking cessation., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Aims: This study estimated annual healthcare expenditures attributable to current e-cigarette use among US adults, including current exclusive and dual/poly e-cigarette use., Methods: Analysing the 2015-2018 National Health Interview Survey data, we estimated the impacts of e-cigarette use on healthcare utilisation among adults aged 18+ years. Healthcare utilisation outcomes were hospital nights, emergency room (ER) visits, doctor visits and home visits. Current e-cigarette use was categorised as exclusive and dual/poly e-cigarette use. The econometric model included two equations: health status as a function of e-cigarette use and other independent variables, and healthcare utilisation as a function of health status, e-cigarette use, and other independent variables. Using an 'excess utilisation' approach, we multiplied the e-cigarette-attributable fraction derived from the model by annual health expenditures to calculate healthcare expenditures attributable to current exclusive and dual/poly e-cigarette use, the sum of which were expenditures attributable to all current e-cigarette use., Results: Current exclusive and dual/poly e-cigarette use, with 0.2% and 3.5% prevalence in 2015-2018, were associated with higher odds of reporting poor health status than never tobacco users. Poor health status was associated with higher odds of using the four healthcare services and a greater number of ER and doctor visits. Annual healthcare expenditures attributable to all current e-cigarette use was $15.1 billion ($2024 per user) in 2018, including $1.3 billion attributable to exclusive e-cigarette use ($1796 per user) and $13.8 billion attributable to dual/poly e-cigarette use ($2050 per user)., Conclusion: Adult current e-cigarette use was associated with substantial excess healthcare utilisation and expenditures., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Previous research quantifying the relationship between tobacco use and food insecurity has focused on cigarette smoking. E-cigarette use has become popular in recent years. Drawing on large, population-based survey data, this study augments the previous research, considering the association of e-cigarette use with food insecurity among low-income adults., Methods: We analysed data from the California Health Interview Survey in 2014-2019. The study sample consisted of 25 948 respondents aged 18-64 who lived in low-income (<200% of the Federal Poverty Level) households. Multivariable logistic regression models were estimated to examine the associations of e-cigarette use as well as dual use of e-cigarettes and cigarettes with food insecurity., Results: Of California low-income adults, 6.4% identified as current e-cigarette users (3.0% dual users of e-cigarettes and cigarettes, and 3.4% sole e-cigarette users) and 43.0% reported food insecurity. After controlling for confounding factors, food insecurity was significantly more likely to be reported among current e-cigarette users (adjusted OR (AOR)=1.67; 95% CI 1.25 to 2.23) compared with never e-cigarette users, and among dual users (AOR=2.21; 95% CI 1.63 to 3.00), current sole e-cigarette users (AOR=1.66; 95% CI 1.15 to 2.40), and current sole cigarette smokers (AOR=1.46; 95% CI 1.22 to 1.76) compared with never tobacco users. The odds of food insecurity among dual users were significantly greater than sole cigarette smokers but not statistically different from sole e-cigarette users., Conclusions: Using e-cigarette is an associated risk factor for food insecurity among low-income adults. Dual use of e-cigarettes and cigarettes has a significantly greater risk of food insecurity compared with smoking cigarettes alone., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

A well designed ring-core fiber can theoretically support numerous orbital angular momentum (OAM) modes with low crosstalk for space-division-multiplexing (SDM) data transmission, which is considered as a promising solution for overcoming the capacity crunch in optical communication network. However, the accumulated chromatic dispersion in OAM-fiber could limit the data speed and transmission distance of communication systems. A potential solution is to insert a dispersion compensation ring-core fiber with opposite-sign of dispersion in the transmission fiber along the fiber link. In this work, we propose a triple ring-core fiber with broadband negative dispersion. A highest negative dispersion of -24.47 ps/(nm·km) at 1550 nm and an average dispersion slope in the C band from -0.182 ps/(nm 2 ·km) to 0.065 ps/(nm 2 ·km) can be achieved to compensate multi-order dispersion. The effects of Ge-doping concentration fluctuation in the high-index ring core and fabrication errors on fiber geometric structures are also investigated. Furthermore, the effective mode area decreases as the widths of high-index rings increase due to the enhanced confinement ability. The designed triple ring-core fiber could offer potential for compensating OAM fiber links with positive dispersions.

We propose and design a 19-ring-air-core fiber that can support about 3000 orbital angular momentum (OAM) modes (156 modes in each ring) with <-80 dB inter-ring cross talk across the entire C and L bands after 100-km fiber propagation. Moreover, the eigenmodes are all separated from their adjacent modes by effective index differences >2.67 × 10 -4 and mode groups by > 1.90 × 10 -2 , which can guarantee the stable transmission of OAM modes. This designed fiber is a potential candidate for applications in spatial division multiplexing (SDM) of optical channels to improve the capacity of next-generation high-speed optical communication systems, especially in short-distance applications. In this Letter, we also show the relationship between supported OAM mode numbers, total cross talk, and effective refractive index of intra-ring modes during the optimization of fiber through numerical simulations. It can provide a related reference for the future design of multi-ring-core fibers.

A Gram-stain-negative bacterium, designated as YN2 T , that is capable of degrading 1,4-dioxane, was isolated from active sludge collected from a wastewater treatment plant in Harbin, PR China. Cells of strain YN2 T were aerobic, motile, pleomorphic rods, mostly twisted, and contained the water-insoluble yellow zeaxanthin dirhamnoside. Strain YN2 T grew at 10-40 °C (optimum, 30 °C), pH 5.0-8.0 (pH 7.0) and with 0-1 % (w/v) NaCl (0.1 %). It also could grow chemolithoautotrophically and fix N 2 when no ammonium or nitrate was supplied. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YN2 T belongs to the genus Xanthobacter and shares the highest pairwise identity with Xanthobacter autotrophicus 7c T (98.6 %) and Xanthobacter flavus 301 T (98.4 %). The major respiratory quinone was ubiquinone-10. Chemotaxonomic analysis revealed that the strain possesses C 16 : 0 , C 19 : 0 cyclo ω 8 c and C 18 : 1  ω7 c as the major fatty acids. The DNA G+C content was 67.95 mol%. Based on genome sequences, the DNA-DNA hybridization estimate values between strain YN2 T and X. autotrophicus 7c T , X. flavus 301 T and X. tagetidis TagT2C T (the only three species of Xanthobacter with currently available genomes) were 31.70, 31.30 and 28.50 %; average nucleotide identity values were 85.23, 84.84 and 83.59 %; average amino acid identity values were 81.24, 80.23 and 73.57 %. Based on its phylogenetic, phenotypic, and physiological characteristics, strain YN2 T is considered to represent a novel species of the genus Xanthobacter , for which the name Xanthobacter dioxanivorans sp. nov. is proposed. The type strain is YN2 T (=CGMCC 1.19031 T =JCM 34666 T ).

As the dimension of orbital angular momentum (OAM) is orthogonal to the other degrees of freedom for photon, such as wavelength, it can be utilized to further increase data capacity in the wavelength division multiplexing (WDM) systems. However, the non-zero dispersion-shifted fiber (NZDSF) for the OAM mode has not yet been investigated or even proposed. In this work, we propose and design a ring fiber with low chromatic dispersion for the HE 2,1 mode, which can serve as NZDSF for its corresponding OAM 1,1 mode. A low dispersion of 3.3 ps/(nm·km) at 1550 nm and <2.9 ps/(nm·km) dispersion variation from 1530 to 1565 nm for the OAM 1,1 mode is achieved in simulation, which satisfies the standard of the ITU-T G.655.C. The designed fiber with ring width from 1.5 µm to 3.5 µm can support the OAM 1,1 mode within the C-band, and a large effective area of about 646 µm 2 is obtained. We also note that the fiber with larger inner radius and ring width are more tolerant to the perturbations, such as fiber ellipticity and bending. In the fiber-based optical communication systems, the designed ring fiber could be used as a candidate for supporting OAM modes with low dispersion and reduced nonlinear effects.