Speckle autocorrelation separation for multi-target scattering imaging.

Imaging through scattering media remains a big challenge in optics while the single-shot non-invasive speckle autocorrelation technique (SAT) is well-known as a promising way to handle it. However, it usually cannot recover a large-scale target or multiple isolated small ones due to the limited effective range of the optical memory effect (OME). In this paper, we propose a multi-target scattering imaging scheme by combining the traditional SA algorithm with a Deep Learning (DL) strategy. The basic idea is to extract each autocorrelation component of every target from the autocorrelation result of a mixed speckle using a suitable DL method. Once we get all the expected autocorrelation components, a typical phase retrieval algorithm (PRA) could be applied to reveal the shapes of all those corresponding small targets. In our experimental demonstration, up to five isolated targets are successfully recovered.

Single-shot noninvasive imaging through scattering medium under white-light illumination.

We experimentally investigate image reconstruction through a scattering medium under white-light illumination. To solve the inverse problem of noninvasive scattering imaging, a modified iterative algorithm is employed with an interpretable constraint on the optical transfer function (OTF). As a result, a sparse and real object can be retrieved whether it is illuminated with a narrowband or broadband light. Compared with the well-known speckle correlation technique (SCT), the proposed method requires no restrictions on the speckle autocorrelation and shows a potential advantage in scattering imaging.

Noninvasive imaging of two isolated objects through a thin scattering medium beyond the 3D optical memory effect.

A speckle image formed by scattering lights can be decoded by recently invented techniques, owing to the optical memory effect, thereby enabling the observation of a hidden object behind a thin scattering medium. However, the range of three-dimensional OME is typically small; therefore, both the field of view and depth of field are limited. We propose a method that can significantly and simultaneously improve both values for a specific scenario, where one object moves around the other position-fixed object. The effectiveness of the proposed scheme is demonstrated through a set of experiments.

Noninvasive imaging of two isolated objects through a thin scattering medium beyond the 3D optical memory effect by speckle-based difference strategy.

The shape of two objects hidden behind a thin scattering medium is retrieved by the presented method. One of the two objects keeps stationary, while the other one is supposed to be gradually moving, and the Euclidean distance between them is always beyond the range of the 3D optical memory effect. We capture two speckle patterns to image the two isolated objects by using a developed speckle-differential-based strategy and the traditional speckle autocorrelation technique. The feasibility of our method is demonstrated by theoretical analysis and a set of experiments.

The associations between meeting 24-hour movement guidelines and adiposity in Asian Adolescents: The Asia-Fit Study.

Less is known about how compliance with 24-hour movement guidelines for physical activity (PA), sedentary behavior, and sleep affects adiposity in young people. The purposes of this study were to compare compliance with 24-hour movement guidelines in Asian adolescents and to examine the associations between compliance with 24-hour movement guidelines and body fat percentage. A sample of 12 590 adolescents aged 13.63 (± 1.01) years from eight Asian metropolitan cities including Bangkok (Thailand), Hong Kong SAR, Kuala Lumpur (Malaysia), Seoul (South Korea), Shanghai (China), Singapore, Taipei (Taiwan), and Tokyo (Japan) completed interviewer-administered questionnaires to assess moderate-to-vigorous PA, recreational screen time, sleep duration, and covariates. Body fat percentage was measured using bioelectrical impedance analysis. We found that compliance with 24-hour movement guidelines differed in Asian adolescents across the eight cities. Adjusting for covariates, there was a negative association between number of the guidelines being met and body fat percentage in Asian adolescents. In addition, meeting only the sleep guideline and both the PA and sleep guidelines had negative associations with body fat percentage compared with no guidelines being met. Our findings improve the understanding about how compliance with 24-hour movement guidelines benefit a healthy body weight in adolescents, as well as contribute to development of evidence-based 24-hour movement guidelines for Asian young people. Future research is needed to gain better insights into the directionality of the associations between compliance with 24-hour movement guidelines and adiposity, as well as the mechanisms underlying the associations in Asian adolescents.

Accelerated skeletal maturation is associated with overweight and obesity as early as preschool age: a cross-sectional study.

BACKGROUND: Body mass index (BMI) and skeletal age (SA) are important indicators of individual growth and maturation. Although the results have not been unified, most studies indicated that accelerated skeletal maturation is associated with overweight/obesity. However, there have so far been insufficient studies about the association between accelerated skeletal maturation and overweight/obesity in preschoolers, particularly Asian children. A cross-sectional study was conducted on Chinese children to verify the association between accelerated skeletal maturation and overweight/obesity at preschool age. METHODS: The study involved 1330 participants aged 3.1-6.6 years old (730 males and 600 females) in Shanghai, China. The skeletal age was determined according to the method of TW3-C RUS. Accelerated skeletal maturation was defined as relative SA (SA minus chronological age [CA]) ≥1.0 years. BMI was classified as thinness, normal weight, overweight, and obesity according to the International Obesity Task Force (IOTF) BMI cut-offs. The Chi-square was performed to determine the statistically significant difference in the frequency of accelerated skeletal maturation in BMI and age categories. The logistic regression model analyzed the association between accelerated skeletal maturation and overweight/obesity. RESULTS: The percentage of accelerated skeletal maturation increased with BMI (7.8% of children in thinness group had accelerated skeletal maturation; the percentage increased to 30.8% in obese group. x2 = 89.442, df = 3, P < 0.01) and age group (at age 3.5, 3.5% of participants had accelerated skeletal maturation; at age 6.0 years, this increased to 27.8%. x2 = 43.417, df = 5, P < 0.01). Logistic regression analysis showed that children with overweight and obesity are more likely to have accelerated skeletal maturation than children with normal weight after adjusting for gender and age (Overweight, odds ratio [OR] = 3.27, 95% confidence interval [CI]: 2.20-4.87; Obese, OR = 4.73, 95% CI: 2.99-7.48). CONCLUSIONS: There is an association between accelerated skeletal maturation and overweight/obesity among preschool children. This study suggests that accelerated skeletal maturation might coexist with overweight/obesity in preschool children, and interventions, such as dietary modifications and increasing levels of physical activity, should be employed to prevent both accelerated skeletal maturation and overweight/obesity as early as preschool age.

Physical activity and health-related fitness in Asian adolescents: The Asia-fit study.

Purpose: The present study aimed to investigate and compare physical activity (PA) and health-related fitness in Asian adolescents, and to examine the associations between meeting PA guidelines and attaining fitness standards. Methods: A sample of 12,590 adolescents (Mage = 13.63 years, SD = 1.01) from eight Asian metropolitan cities completed measurements of PA, five field-based fitness tests, and covariates. The fitness test scores were further classified into Healthy Fitness Zone (HFZ) or Needs Improvement Zone (NIZ). Results: Findings showed that adolescents' levels of PA and fitness components differed by cities. City differences were also found in proportions of meeting PA guidelines and achieving the HFZs of aerobic capacity, muscular fitness, and body composition. After controlling covariates, meeting PA guidelines positively associated with being in the HFZs of aerobic and muscular fitness, but the association was not significant with being in the body composition HFZ. Conclusion: There was a large variation in PA and health-related fitness in adolescents across the eight Asian cities. Asian adolescents achieving PA guidelines were more likely to be in the HFZ of aerobic and muscular fitness. Prospective follow-up studies are warranted to gain better insights into the relationships between objectively-measured PA and fitness.

ACTN3 is associated with children's physical fitness in Han Chinese.

The ACTN3 gene locates on 11q13-q14 and encodes the α-actinin-3 protein, which is only expressed in human skeletal muscle and influenced muscle function and metabolism. The previous studies reported that SNP rs1815739 is associated with elite power athletes' performance. In this study, we investigated the association between five SNPs within the ACTN3 gene and Chinese children physical fitness. We recruited 2244 Han Chinese children participants, and measured their 25-m run, stand broad jump, 10-m shuttle run, handgrip, BMI (calculated by weight and height) data. SNPs rs1671064, rs2275998, rs2290463, rs10791881, and rs1815739 of ACTN3 gene were genotyped and analyzed in five physical fitness data. QTL analysis on genotype and physical fitness data was carried out in all samples. Furthermore, a dichotomous division of samples into an overweight group (543) and a normal group (1701) was used for an association study of overweight. In the QTL analysis, we found rs2290463 was significantly associated with stand broad jump (corrected P value = 0.009, beta = 2.692). After added age and gender as covariates in the regression test, the association became more significant (P value = 5.80 × 10- 5, corrected P value = 4.06 × 10- 4); when we used BMI as a covariate, the association still existed (P value = 4.65 × 10- 4, corrected P value = 0.001). In the association study of overweight, rs2275998 was found to be significant (OR, 95% CI = 0.733 [0.6-0.895]; Pallele = 0.011, Pgenotype = 0.024) after the Bonferroni correction, and the association did not change much after a further correction for gender, age, and stand broad jump performance. Our results showed that common variants in ACTN3 are significantly associated with both stand broad jump performance and overweight in Han Chinese children.

Cryptanalysis of random-phase-encoding-based optical cryptosystem via deep learning.

Random Phase Encoding (RPE) techniques for image encryption have drawn increasing attention during the past decades. We demonstrate in this contribution that the RPE-based optical cryptosystems are vulnerable to the chosen-plaintext attack (CPA) with deep learning strategy. A deep neural network (DNN) model is employed and trained to learn the working mechanism of optical cryptosystems, and finally obtaining a certain optimized DNN that acts as a decryption system. Numerical simulations were carried out to verify its feasibility and reliability of not only the classical Double RPE (DRPE) scheme but also the security-enhanced Tripe RPE (TRPE) scheme. The results further indicate the possibility of reconstructing images (plaintexts) outside the original data set.

Compressive optical steganography via single-pixel imaging.

A compressive optical steganography based on single-pixel imaging (SPI) is proposed. The SPI system, which employs a digital light projector to illuminate the host image with modulated patterns, is similar to a wireless broadcast system. Therefore, it is suitable for covert communication naturally. By leveraging the compressive sensing technique and a generalized phase retrieval algorithm, the secret message is sparse-sampled and then encoded into the illumination patterns, which are projected onto the host image in an SPI architecture. The resulting reflected light signals travel in the free space as a broadcast system, and the signals would be captured by the authorized receivers and the potential eavesdroppers. By implementing an inverse Fourier transform, a stegoimage will be received, which is almost the same as the host image. However, only the authorized receivers, who possess the secret key, could extract the desired data from the stegoimage and then reconstruct the secret message by using a convex optimization algorithm. Because the secret message is sparse-sampled before embedding, the imperceptibility is well preserved while the capacity also be kept in a high level. A series of simulation and experimental results verifies the validity and feasibility of the proposed method.

Improving reconstruction of speckle correlation imaging by using a modified phase retrieval algorithm with the number of nonzero-pixels constraint.

Speckle correlation imaging (SCI) has been considered one of the most promising techniques for computational imaging through a scattering medium. However, the image quality is not always acceptable in conventional SCI, especially when a complex object is involved. In this work, a modified phase retrieval algorithm is introduced to significantly improve the imaging quality of SCI. In the proposed scheme, nonzero-pixel constraints, rather than the real and nonnegative constraints, are employed as the object domain constraints of the iterative algorithm in the image reconstruction process. Experimental results are presented to show the performance enhancement of this scheme, inclusive of less iterations, better image quality, and higher reliability, in comparison with the conventional SCI method.

Moderate-to-vigorous physical activity attenuates the detrimental effects of television viewing on the cardiorespiratory fitness in Asian adolescents: the Asia-fit study.

BACKGROUND: Moderate-to-vigorous physical activity (MVPA) and television viewing are independently associated with cardiorespiratory fitness. However, limited evidence is available on their combined effects, specifically of MVPA and watching television, on cardiorespiratory fitness in the young Asian population. Therefore, the present study examined whether MVPA can attenuate the detrimental effects of prolonged television viewing on the cardiorespiratory fitness of Asian adolescents. METHODS: This is a cross-sectional study on 9553 adolescents (aged 12-15 years) from 8 Asian metropolitan cities (Tokyo, Hong Kong, Shanghai, Taipei, Bangkok, Kuala Lumpur, Seoul, and Singapore). Cardiorespiratory fitness was assessed by using a 15-m progressive aerobic capacity endurance run (PACER) test. The time spent on MVPA and watching television was assessed using the International Physical Activity Questionnaire-Short Form. RESULTS: MVPA was more closely associated with the PACER score than the duration of watching television. Compared with the reference group (i.e. those with the lowest levels of MVPA [< 30 min/day] and the most sedentary [≥3 h/day of television time]), PACER scores were significantly higher for those who met the physical activity recommendation (≥60 min/day in MVPA), regardless of the duration of television viewing. Conversely, girls in the least active group (< 30 min/day of MVPA) who watched television < 1 h/day demonstrated better PACER scores than the reference group. CONCLUSIONS: Sufficient MVPA (≥60 min/day) can attenuate the detrimental effects of excessive television viewing with cardiorespiratory fitness in Asian adolescents. In addition, the duration of television viewing had significant but weaker associations with cardiorespiratory fitness compared to MVPA.

Polymorphism of the PPARD Gene and Dynamic Balance Performance in Han Chinese Children.

BACKGROUND: Athletic performances are complex traits with heritability of ~66%. Dynamic balance is one of the most important athletic performances, and there has been little studies for it in sports genomics. The candidate PPARD gene was reported to be able to affect muscle development for balance predisposition and influence the athletic performance including skiing triumph in the Caucasian population. This study aims to investigate whether the PPARD gene is a susceptibility gene for dynamic balance performance in Han Chinese children. RESULTS: A total 2244 children were recruited and their balance beam performances were measured. Five polymorphisms in the PPARD gene were genotyped through the MassARRAY Sequenom platform. Rs2016520 exerted significant association with dynamic balance performance (minor allele C, P = 0.015, Pcorrected < 0.05) and was affirmed in a meta-analysis by combining previously reported Caucasian cohorts (OR = 1.57, 95% CI = [1.30, 1.91], P < 10 -5) . Another polymorphism, rs2267668, was also significantly associated with dynamic balance performance (minor allele G, P = 0.015, Pcorrected < 0.05). In the dichotomous study, 321 cases (61% boys and 39% girls) and 370 controls (49% boys and 51% girls) in our samples were selected as representatives, and the thresholds were the mean velocity (0.737 m/s) ± standard deviation (0.264 m/s), in which rs2016520-C and rs2267668-G still remained significant (CI =1.41 [1.11~1.79], P = 0.004, Pcorrected < 0.016; CI =1.45 [1.14~1.86], P = 0.002, Pcorrected < 0.016). In different genders, consistent OR direction was observed for each variant. CONCLUSIONS: Our results suggested that the PPARD gene is associated with dynamic balance performance of human being, and further studies to reveal its etiology is strongly suggested.

Relationship between Muscle Mass/Strength and Hepatic Fat Content in Post-Menopausal Women.

Background and Objectives: Recent studies have shown that low skeletal muscle mass can contribute to non-alcoholic fatty liver disease through insulin resistance. However, the association between muscle mass/strength and hepatic fat content remains unclear in postmenopausal women. Methods: In this study, we assessed the associations between muscle mass/strength and various severities of non-alcoholic fatty liver disease. Using single-voxel proton magnetic resonance spectroscopy, 96 postmenopausal women between the ages of 50 and 65 were divided into four groups (G0-G3) by hepatic fat content: G0 (hepatic fat content <5%, n = 20), G1 (5% ≤ hepatic fat content < 10%, n = 27), G2 (10% ≤ hepatic fat content < 25%, n = 31), and G3 (hepatic fat content ≥25%, n = 18). Muscle mass indexes were estimated as skeletal muscle index (SMI)% (total lean mass/weight × 100) and appendicular skeletal muscular mass index (ASM)% (appendicular lean mass/weight × 100) by dual energy X-ray absorptiometry. Maximal isometric voluntary contraction of the handgrip, elbow flexors, and knee extensors was measured using an adjustable dynamometer chair. Fasting plasma glucose, insulin, and follicle-stimulating hormones were assessed in venous blood samples. Results: The results showed negative correlations between hepatic fat content and SMI% (r = -0.42, p < 0.001), ASM% (r = -0.29, p = 0.005), maximal voluntary force of grip (r = -0.22, p = 0.037), and knee extensors (r = -0.22, p = 0.032). Conclusions: These significant correlations almost remained unchanged even after controlling for insulin resistance. In conclusion, negative correlations exist between muscle mass/strength and the progressed severity of non-alcoholic fatty liver disease among post-menopausal women, and the correlations are independent of insulin resistance.

Association study of NDST3 gene for schizophrenia, bipolar disorder, major depressive disorder in the Han Chinese population.

The NDST3 gene at 4q26 was a functional candidate gene for mental disorders. Recently, a novel genome-wide significant risk locus at chromosome 4q26 was identified and the top single nucleotide polymorphism rs11098403 in the vicinity of NDST3 gene was reported to confer risk of schizophrenia in Caucasian. Nevertheless, association between NDST3 gene polymorphisms and schizophrenia, bipolar disorder, or major depressive disorders has not been well studied in the Han Chinese population. To further investigate whether NDST3 is a risk gene for these mental disorders, we genotyped and analyzed eight tag SNPs (rs11098403, rs10857057, rs2389521, rs4833564, rs6837896, rs7689157, rs3817274, rs609512) covering NDST3 gene in 1,248 schizophrenia cases, 1,056 major depression cases, 1,344 bipolar disorder cases, and 1,248 controls of Chinese origin. However, there was no significant difference in allelic or genotypic frequency observed between each case group and healthy controls. Accordingly, our study does not support that the NDST3 gene plays a major role in schizophrenia, bipolar disorder, and major depressive disorder in the Han Chinese population.

Polarization-insensitive perfect absorption in van der waals hyper-structure.

Infrared perfect absorption has been widely investigated due to its potential applications in photodetectors, photovoltaics and medical diagnostics. In this report, we demonstrate that at particular infrared frequencies, a simple planar structure made up of graphene-hexagonal Boron Nitride (hBN) hyper-structure is able to nearly perfectly absorb incident light irrespective of its polarization (Transverse-Magnetic TM, or Transverse-Electric TE). By using this interferenceless technique, the hyper-structure achieves nearly zero reflectance at a wide range of angles in a narrow frequency band. We analytically predict the condition of achieving such an important feature of perfect absorption for both TM and TE polarizations. Interestingly, the infrared perfect absorption can be redshifted by increasing the thickness of the hBN layers and blueshifted by increasing the graphene's chemical potential. Such flexible control of infrared perfect absorption offers a new tool for controlling electromagnetic waves and has potential applications in photodetection and other light control applications.

Combining glycosylated hemoglobin A1c and fasting plasma glucose for diagnosis of type 2 diabetes in Chinese adults.

BACKGROUND: Glycosylated hemoglobin A1c (HbA1c) has been applied to identify type 2 diabetes (T2DM) in the U.S. and European countries. It has not been used in China mainly due to lack of a standardized approach to measure HbA1c, short of knowledge about racial-specific standard and deficiency of an optimal cut-off point. METHODS: To evaluate combination of HbA1c and fasting plasma glucose (FPG) in diagnosing T2DM in Chinese adults, a multistage sampling cross-sectional study was conducted in Shanghai, China, in 2009. The FPG measurement, HbA1c assay, and oral glucose tolerance test (OGTT) were performed in 6,661 Chinese adults (3057 men, 3604 women) who had no prior history of diabetes to identify the unrecognized T2DM. RESULTS: A total of 454 participants were identified as T2DM based on the 1999 World Health Organization (WHO) diagnostic criteria. Of these patients, 239 were detected using an FPG ≥ 7.0 mmol/l and 141 were further identified using an HbA1c ≥ 43 mmol/mol (6.1%), achieving a sensitivity of 83.7% and a specificity of 89.3% for combining use of FPG and HbA1c. In subjects at high risk of diabetes, the combining use of FPG and HbA1c produced a higher sensitivity and an improved positive predictive value (PPV), and had a satisfactory specificity and negative predictive value (NPV). CONCLUSIONS: The combining use of FPG and HbA1c is a potential screening and diagnosis approach for T2DM in Chinese adults, especially among those at high risk of the disease.

Qualitative study of the association between psychosocial health and physical activity/sleep quality in toddlers.

Physical activity and sleep are important factors of mental and physical health in children, with some reports indicating that their effects can persist into adulthood. However, there is limited research on the qualitative aspects of physical activity and sleep in preschool children, particularly in those aged < 3 years. Therefore, to elucidate the association between psychosocial health and physical activity/sleep in early childhood in terms of qualitative aspects, we conducted a retrospective cohort study in 2985 3-year-old children (37.2 ± 0.75 months) in Shanghai, China. An analysis using structural equation modeling indicated that current physical activity had a direct and moderate impact on current psychosocial health evaluated using the Strength and Difficulties Questionnaire. In particular, past physical activity had an indirect and mild effect on current psychosocial health via current physical activity in girls. However, regardless of sex, past sleep quality had slight impact on current psychosocial health, not only indirectly via current sleep quality, but also directly. These findings highlight the importance of considering the qualitative aspects of physical activity and sleep quality as significant factors influencing the current and future psychosocial health of children, even at a very early age (< 3 years).

Associations of Morphological Changes in Skeletal Muscles of Preschool Children in China Following Physical Activity.

PURPOSE: Physical activity (PA) is likely to be the most important modifiable factor in skeletal muscle development. However, the influence of PA on the skeletal muscle of preschool children has not been thoroughly investigated. The main objective of this study was to quantitatively measure PA, and then, to assess whether associations exist between site-specific muscle changes and PA in relation to sex and weight statuses in preschool children aged 3 to 4 years. METHODS: A total of 86 healthy preschool children, aged 3-4 years, were instructed to wear an accelerometer for seven consecutive days. The number of steps taken daily, and minutes spent in moderate-vigorous PA (MVPA) and total PA (TPA) were recorded. Muscle thickness was measured by B-mode ultrasonography using a 5-18 MHz scanning head. Muscle thickness was measured at seven sites: the lateral forearm, upper arm, abdomen, anterior and posterior thigh, and anterior and posterior lower leg. RESULTS: There was no significant difference between boys and girls in terms of MVPA and TPA on weekdays and weekends. According to the linear regression models, after adjusting for daylight duration, the muscle of the posterior thigh was significantly positively associated (p < 0.05) with daily steps and MVPA on weekdays for boys and girls, respectively. CONCLUSIONS: We found that the muscle thickness of the posterior thigh in preschool children was significantly positively associated with PA, as measured by daily steps and MVPA. We suggest that for the overall health and well-being of preschool children, the levels of PA should be maintained and/or increased, and preferably transformed into a regular part of daily living.

Estimability study on the age of toddlers' gait development based on gait parameters.

In the first few years of toddlers' locomotion, various gait parameters improve gradually and dynamically with gait development. Therefore, in this study, we hypothesized that the age of gait development, or the level of gait development with age as its indicator, can be estimated from several gait parameters related to gait development, and investigated its estimability. In total, 97 healthy toddlers aged about 1-3 years participated in the study. All five selected gait parameters showed a moderate or higher correlation with age, but the duration with a large change and the strength of the association with gait development varied for each gait parameter. Multiple regression analysis was performed using age as the objective variable and five selected gait parameters as explanatory variables, and an estimation model (R2 = 0.683, adjusted R2 = 0.665) was created. The estimation model was verified using a test dataset separate from the training dataset (R2 = 0.82, p < 0.001). It was suggested that the age of gait development could be estimated from gait alone. Gait analysis based on empirical observations may reduce the need for skilled observers and their potential variability.