Note on the Persistence of a Nonautonomous Lotka-Volterra Competitive System with Infinite Delay and Feedback Controls

We study a nonautonomous Lotka-Volterra competitive system with infinite delay and feedback controls. We establish a series of criteria under which a part of n-species of the systems is driven to extinction while the remaining part of the species is persistent. Particularly, as a special case, a series of new sufficient conditions on the persistence for all species of system are obtained. Several examples together with their numerical simulations show the feasibility of our main results

Nonnegative Matrix Factorization Numerical Method for Integrated Photonic Cavity Based Spectroscopy

Nonnegative matrix factorization numerical method has been used to improve the spectral resolution of integrated photonic cavity based spectroscopy. Based on the experimental results for integrated photonic cavity device on Optics Letters 32, 632 (2007), the theoretical results show that the spectral resolution can be improved more than 3 times from 5.5 nm to 1.8 nm. It is a promising way to release the difficulty of fabricating high-resolution devices

Circadian Clock Genes in the Metabolism of Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a common disease, which is characterized by the accumulation of triglycerides in the hepatocytes without excess alcohol intake. Circadian rhythms can participate in lipid, glucose, and cholesterol metabolism and are closely related to metabolism seen in this disease. Circadian clock genes can modulate liver lipid metabolism. Desynchrony of circadian rhythms and the influences imparted by external environmental stimuli can increase morbidity. By contrast, synchronizing circadian rhythms can help to alleviate the metabolic disturbance seen in NAFLD. In this review, we have discussed the current research connections that exist between the circadian clock and the metabolism of NAFLD, and we have specifically focused on the key circadian clock genes, Bmal1, Clock, Rev-Erbs, Rors, Pers, Crys, Nocturnin, and DECs

Ultrahigh-Frequency Surface Acoustic Wave Sensors with Giant Mass-Loading Effects on Electrodes

Surface acoustic wave (SAW) devices are widely used for physical, chemical, and biological sensing applications, and their sensing mechanisms are generally based on frequency changes due to mass-loading effects at the acoustic wave propagation area between two interdigitated transducers (IDTs). In this paper, a new sensing mechanism has been proposed based on a significantly enhanced mass-loading effect generated directly on Au IDT electrodes, which enables significantly enhanced sensitivity, compared with that of conventional SAW devices. The fabricated ultrahigh-frequency SAW devices show a significant mass-loading effect on the electrodes. When the Au-electrode thickness increased from 12 to 25 nm, the Rayleigh mode resonant frequency decreased from 7.77 to 5.93 GHz, while that of the higher longitudinal leaky SAW decreased from 11.87 to 9.83 GHz. The corresponding mass sensitivity of 7309 MHz·mm2·μg–1 (Rayleigh mode) is ∼8.9 × 1011 times larger than that of a conventional quartz crystal balance (with a frequency of 5 MHz) and ∼1000 times higher than that of conventional SAW devices (with a frequency of 978 MHz). Trinitrotoluene concentration as low as 4.4 × 10–9 M (mol·L–1) can be detected using the fabricated SAW sensor, proving its giant mass-loading effect and ultrahigh sensitivity

30 GHz surface acoustic wave transducers with extremely high mass sensitivity

A nano-patterning process is reported in this work, which can achieve surface acoustic wave (SAW) devices with an extremely high frequency and a super-high mass sensitivity. An integrated lift-off process with ion beam milling is used to minimize the short-circuiting problem and improve the quality of nanoscale interdigital transducers (IDTs). A specifically designed proximity-effect-correction algorithm is applied to mitigate the proximity effect occurring in the electron-beam lithography process. The IDTs with a period of 160 nm and a finger width of 35 nm are achieved, enabling a frequency of ∼30 GHz on lithium niobate based SAW devices. Both centrosymmetric type and axisymmetric type IDT structures are fabricated, and the results show that the centrosymmetric type tends to excite lower-order Rayleigh waves and the axisymmetric type tends to excite higher-order wave modes. A mass sensitivity of ∼388.2 MHz × mm2/μg is demonstrated, which is ∼109 times larger than that of a conventional quartz crystal balance and ∼50 times higher than a conventional SAW device with a wavelength of 4 μm

Feedback control effect on the Lotka-Volterra prey-predator system with discrete delays

Abstract In this paper, we study a Lotka-Volterra prey-predator system with feedback control. We establish sufficient conditions under which a unique positive equilibrium is globally stable. Further, we show that a suitable feedback control on predator species can make prey species that is on the brink of extinction become globally stable, but under the conditions of small feedback control on predator, the prey species still extinct, whereas the predator species is stable at certain values. Several examples are presented to show the feasibility of the main results

Exploring Different Patterns of Love Attitudes among Chinese College Students

<div><p>Individual differences in love attitudes and the relationship between love attitudes and other variables in Asian culture lack in-depth exploration. This study conducted cluster analysis with data regarding love attitudes obtained from 389 college students in mainland China. The result of cluster analysis based on love-attitude scales distinguished four types of students: game players, rational lovers, emotional lovers, and absence lovers. These four groups of students showed significant differences in sexual attitudes and personality traits of deliberation and dutifulness but not self-discipline. The study’s implications for future studies on love attitudes in certain cultural groups were also discussed.</p></div

Prevalence and factors associated with nonalcoholic fatty liver disease in shanghai work-units

Abstract Backgrounds Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease in Asians. However, data on prevalence and factors associated with NAFLD in Asians are lacking. The aim of this study is to investigate the prevalence of NAFLD in Shanghai employees to assess the relationship between NAFLD and age, gender, metabolic risk factors in this studied population. Methods We selected 7152 employees of Shanghai work-units. Each of them underwent detailed medical history-taking, physical examination, laboratory assessments and abdominal ultrasonography. The diagnosis of NAFLD was done according to established criteria. Receiver operating characteristics (ROC) curves were applied to detect areas under the ROC curves for each index. Nominal logistic regression analysis was used to estimate the odds ratio for risk factors of NAFLD. Results About 38.17% employees had NAFLD, more in men than in women. The prevalence of NAFLD increased with increasing age. In both genders, the prevalence of metabolic factors was higher in the NAFLD group. Body max index, waist circumference, weight-to-height ratio, blood pressure, blood glucose, total cholesterol, triglyceride, low density lipoprotein, high density lipoprotein and uric acid were found to have a diagnostic value for NAFLD. Body max index is a better index for diagnosing NAFLD. Uric acid is a new diagnosing index not inferior to lipid metabolic factors. Metabolic factors can increase the risk of NAFLD up to 1.5 ~ 3.8 times. Conclusions Older age, male gender, metabolic factors such as obesity, abdominal obesity, dyslipidemia, hypertension or type 2 diabetes are risk factors for NAFLD. Prevalence of NAFLD in Shanghai employees is high. Prevention is extremely important. Those achieve the critical point should have early intervention.</p