[Comorbidity of anxiety symptoms and depression symptoms among middle and high school students in Zhejiang Province].

Objective: To analyze the epidemiological patterns of comorbidity of anxiety symptoms and depression symptoms among middle and high school students in Zhejiang Province and to provide evidence for making strategy and evaluation of intervention. Methods: Through a multi-stage sampling design, 28 043 students from 376 schools in 30 counties/districts were recruited and surveyed using anonymous self-administered questionnaires in classrooms under the supervision of trained staff between April and June 2022. Anxiety symptoms were assessed using generalized Anxiety Disorders 7-Item Scale, and depression symptoms were assessed using Patient Health Questionnaire 9-Item Depression Scale. A total of 27 004 students were included in the final analysis. Results: The overall prevalence of comorbidity of anxiety symptoms and depression symptoms was 11.54% (95%CI: 10.90%-12.19%), higher among girls (15.42%, 95%CI: 14.47%- 16.38%) than boys (8.05%, 95%CI: 7.43%-8.67%) (P<0.001), higher among students living in rural areas (12.35%, 95%CI: 11.49%-13.22%) than those in urban areas (10.06%, 95%CI: 9.27%-10.86%) (P<0.001). The prevalence of comorbidity of students attending middle school, academic high school, and vocational high school was 11.73% (95%CI: 10.82%-12.64%), 12.49% (95%CI: 11.20%- 13.79%), and 9.98% (95%CI: 8.68%-11.27%), respectively (P=0.025). The prevalence of comorbidity was higher among students in divorced/widow/separated families (16.64%, 95%CI: 14.86%-18.43%) than those in intact families (10.82%, 95%CI: 10.14%-11.50%) (P<0.001). The wealthier the families, the lower the prevalence of comorbidity (P<0.001). The prevalence of comorbidity was higher among cigarettes smokers in the past 30 days (21.70%,95%CI: 18.24%- 25.16%) than non-smokers (11.13%, 95%CI: 10.51%-11.76%), higher among alcohol drinkers in the past 30 days (19.36%, 95%CI: 17.58%-21.14%) than non-drinkers (10.05%, 95%CI: 9.43%- 10.68%), higher among students engaging in physical fight in the past 12 months (18.42%, 95%CI: 16.75%-20.09%) than those without physical fight (10.45%, 95%CI: 9.81%-11.10%). The more frequently students engaged in physical exercise, the lower the prevalence of comorbidity (P<0.001). The poorer the academic performance self-reported, the higher the prevalence of comorbidity (P<0.001). Conclusion: More than one-tenth of middle and high school students in Zhejiang Province have comorbidity of anxiety symptoms and depression symptoms, and more attention should be paid to adolescent mental health.

[The prevalence of insufficient physical activity and the influencing factors among Chinese adults in 2018].

Objective: To understand the prevalence of insufficient physical activity among adults aged ≥18 years in China and to explore the influencing factors. Methods: The China Chronic Disease and Risk Factor Surveillance was conducted in 298 counties/districts in China in 2018, covering 31 provinces (autonomous regions, municipalities). A multi-stage stratified cluster random sampling method was used to select permanent residents aged ≥18 years. A questionnaire including Global Physical Activity Questionnaire was used to collect information about the participants' demographic characteristics and physical activity through face-to-face interview. A total of 183 769 participants completed the survey. After complex data weighting, the prevalence of insufficient physical activity, occupation, transportation, and leisure-time physical activity time was analyzed. Multivariate logistic regression models were used to analyze the influencing factors related to insufficient physical activity. Results: The prevalence of insufficient physical activity among adults aged ≥18 years was 22.3% (95%CI: 20.9%-23.7%) in China in 2018, with males [24.4% (95%CI: 23.0%-25.8%)] significantly higher than females [20.2% (95%CI: 18.6%-21.8%)]. Adults aged 70 years and above [28.4% (95%CI: 26.9%-29.9%)] were significantly higher than adults in other age groups, followed by adults aged 18-29 years [26.4% (95%CI: 24.4%- 28.3%)] and 30-39 years [23.4% (95%CI: 21.5%-25.3%)], and tended to increase with increasing education and total sedentary behavior time (P<0.001). The weekly occupation, transportation, and leisure-time physical activity time appeared 958.6 (95%CI: 911.4-1 005.8) minutes, 234.5 (95%CI: 224.7- 244.2) minutes, and 88.6 (95%CI: 83.5-93.7) minutes, respectively. Multivariate logistic regression analysis showed that males, adults living in rural areas or northern China, ≥70 years, with junior high school education, an annual household income per capita <6 000 yuan and institutional/clerical/ technical occupation and longer total sedentary behavior time were related to a higher prevalence of insufficient physical activity. Conclusions: In China, over one-fifth of the adults had lower physical activity levels. Adults who are male, young adults, more educated, institutional/clerical/technical occupation, and with more extended total sedentary behavior are the populations that need to be focused on to promote physical activity-related health.

[Association between self-reported gingival bleeding and prevalent hypertension among adults in a cross-sectional study in Zhejiang province].

Objective: To explore the association between self-reported gingival bleeding and prevalent hypertension among adults in Zhejiang with a cross-sectional study. Methods: After excluding participants with self-reported, physician-diagnosed heart diseases, stroke, diabetes, cancer, and those who never or rarely brush their teeth at baseline study, 48 625 participants aged 30-79 in the China Kadoorie Biobank (CKB) study from Tongxiang, Zhejiang were included for the final analysis. Three multivariable logistic regression models were used to estimate the odds ratios (ORs) for the associations of self-reported gingival bleeding with prevalent hypertension. Results: The mean age of women was (51.2±9.2) years, and 42.9% of participants had prevalent hypertension. The percentage of self-reported frequent gingival bleeding was 6.56% (95%CI: 6.38%-6.75%), significantly higher among women (8.08%, 95%CI: 7.82%-8.35%) than among men (4.36%, 95%CI: 4.12%-4.60%) (P<0.001). After adjusting for socio-demographic factors, behavioral lifestyle, sleep duration, BMI, waist circumference, snoring, in comparison with men whose gingivae never or rarely bleed while brushing teeth, the odds ratio (95%CI) of hypertension for those with occasional, and frequent gingival bleeding were 1.04 (0.96-1.12) and 1.18 (1.02-1.37), respectively (trend P =0.038). The corresponding figures for women were 0.96 (0.91-1.02) and 0.95 (0.86-1.05), respectively (trend P=0.344). Conclusion: Frequent gingival bleeding was positively associated with prevalent hypertension among men.

Differences in corneal and anterior segment morphology between diabetic vs. healthy children and adolescents: a systematic review and meta-analysis.

OBJECTIVE: To compare corneal and anterior segment morphology among children and adolescents with and without diabetes. MATERIALS AND METHODS: PubMed, Embase and Scopus databases were systematically searched. Studies that were observational in design were considered. Included studies should have been done in young children and/or adolescents and compared relevant outcomes of interest based on the diabetic status. The outcomes of interest were related to corneal morphology, morphology of lens, as well as important characteristics of anterior segment such as depth, pupillary diameter, intra-ocular pressure and axial length. The pooled effect sizes were reported as weighted mean difference (WMD). STATA software was used for statistical analysis. RESULTS: The meta-analysis included 17 studies. Diabetic children had lower corneal endothelial cell density (cells/mm2) (WMD -215.7, 95% CI: -406.5, -24.9), higher central corneal thickness (µm) (WMD 12.66, 95% CI: 5.47, 19.84), higher lenticular thickness (mm) (WMD 0.25, 95% CI: 0.13, 0.36) and density (WMD 3.02, 95% CI: 2.23, 3.81) than non-diabetic children. The anterior chamber depth (mm) (WMD -0.17, 95% CI: -0.24, -0.09) and pupillary diameter (mm) (WMD -0.61, 95% CI: -1.12, -0.10) was significantly reduced in diabetic children, compared to non-diabetic children. No differences in the corneal curvature, corneal diameter, spherical equivalent, intra-ocular pressure, axial length, tear film breakup time and Schirmer test were noted among diabetic and non-diabetic children. CONCLUSIONS: Significant structural changes in cornea and lens along with reduction in anterior chamber depth and pupillary diameter were found. These morphological changes may be indication for early and prompt management and underscore the need for more advanced ophthalmological evaluation techniques, in addition to routine examination.

[Association between alcohol consumption and insomnia in employed floating population in China].

Objective: To explore the relationship between alcohol consumption and insomnia among 18-59 years old employed floating population in mainland China, and provide scientific basis for the relevant policies to improve the sleep status of employed floating population from the perspective of alcohol consumption. Methods: Data were from Chinese Floating Population Chronic Disease Surveillance (2012). Floating population were selected from industries in 170 counties and districts of 31 provinces/autonomous regions, and Xinjiang Construction Corps in mainland China by using the stratified multistage cluster sampling. Demographic information, behavioral risk factors, insomnia, social pressure and chronic diseases were collected through using the face-to-face questionnaire. After complex weighting of the data, a multivariable logistic regression was used to explore the sleep status and its influencing factors among the employed floating population. Results: A total of 48 499 subjects were included in the analysis. The proportions of the employed floating population who never drank alcohol, drank small amount, and drank excessively were 48.3%, 41.8% and 9.9%, respectively. The prevalence of insomnia among the general, male and female employed floating population was 28.6%, 25.8% and 32.3%, respectively. The prevalence of insomnia among the employed floating population aged between 45 and 59 years old (32.2%) was higher than that in the population aged between 18 and 44 years old (28.2%). The multivariable logistic regression analysis showed that after adjusting confounding factors, compared with the employed floating population who never consumed alcohol as the reference group, the OR values of insomnia for the employed floating population with moderate drinking and excessive drinking were 1.40 and 1.53, respectively. The OR values of insomnia for the male and female employed floating population with moderate drinking were 1.28 and 1.53. The OR values of insomnia for the male and female employed floating population with excessive drinking were both 1.46. The OR values of insomnia for the population aged 18-44 years and 45-59 years with excessive drinking were 1.41 and 1.27. The OR values of insomnia for the population aged 18-44 years and 45-59 years with excessive drinking were 1.55 and 1.37. Conclusion: Small amount of drinking and excessive drinking are associated with insomnia among the employed floating population in mainland China. The association between excessive drinking and insomnia is stronger than that between small amount of drinking and insomnia.

[Association between sleep status and prevalence of major chronic diseases].

Sleep is an important physiological activity. With the changing life style in this modern world, the average duration of sleep in human beings is decreasing, and the prevalence of sleep disorder or insomnia is increasing. Short duration and disorders of sleep or insomnia may often lead to increased prevalence/incidence of major chronic diseases such as hypertension, diabetes, obesity and dyslipidemia. Currently, chronic diseases have become the main causes of death and with high disease burden among the Chinese. In the Healthy China Initiative (2019-2030), prevention and control of chronic diseases including "moving forward" , "slowing down the upward trend of the prevalence of insomnia" as the expected indices and "extending the sleep duration of adults to 7-8 hours a day" as the advocacy index, were all called for. In this group of articles, basic data for sleep status of adults in different regions of the country was provided to help understand the relations between sleep and major chronic diseases, and strategies related to prevention and control of chronic diseases.

[Status of sleep and influencing factors in employed floating population in China].

Objective: To understand the sleep status and related influencing factors among 18-59 years old employed floating population and to provide evidence for policy development. Methods: Data were gathered from the Chinese Floating Population Chronic Disease Surveillance (2012) program. Floating population were selected through multistage clustering sampling method and stratified by industries from China. Information on demographics, behavior-related risk factors, sleep duration and social pressure etc., were collected through face-to-face interview on questionnaires. After complex weighting of data, multivariable logistic regression method was used to explore the sleep status and related influencing factors among these employed floating people. Results: A total of 43 521 subjects were included in the study. The average sleep duration per day was 7.77 h, with females (7.87 h) higher than males (7.69 h). The prevalence of insufficient sleep was 12.3% (95%CI: 11.8%-12.7%), with 45-59 years old group (21.2%) higher than that of the 18-year olds (11.2%). Results from the multivariable logistic regression analysis showed that factors as gender, age, marital status, education, occupation, inflowing area, behavior-related risk factors, BMI, social pressure, self-rated health status and self-reported chronic diseases were the main factors that affecting the rates of sleep deficiency in this population. The prevalence rate of insufficient sleep was 1.18 times higher (95%CI: 1.07-1.31) in males than that in females, and 1.22 (95%CI: 1.11-1.33) times higher in smokers than that in the non-smokers, 1.31(95%CI: 1.16-1.49) times higher in excessive drinkers than that of the normal population, 1.46 (95%CI: 1.29-1.65) times and 1.33 (95%CI: 1.18-1.50) times in those with heavier workload and stress than those without. Conclusion: The prevalence of insufficient sleep among the employed floating population was affected by multiple factors that called for more attention by different departments of the government.

[Relationship between eating behavior and obesity among Chinese adults].

Objective: To study the relationship between eating behavior and obesity among Chinese adults. Methods: Data were collected from 171 040 people who had been engaged in the 2013 China Chronic and Non-communicable Disease and Risk Factors Surveillance project. Rao-Scott χ(2) test and complex sampling design were used to compare the differences in the rates of eating behavior and obesity. A binary logistic regression model based on complex sampling design was used to investigate the relationship between eating behavior at three meals (breakfast, lunch and dinner) and obesity. Results: The proportion (3.3%) of skipping breakfast appeared the highest. Proportions of eating out for all the three meals were 16.4%, 21.4% and 11.7%, respectively. The prevalence rates of obesity among men who ate lunch at home, ate out or skipped the lunch were 13.2%, 16.1% and 15.9%, respectively. The prevalence rates of obesity among women who ate lunch at home, ate out or skipped lunch were 14.5%, 9.8%, 19.6%, respectively. Results from the multivariate logistic regression analysis showed that eating out for lunch and skipping lunch were both positively correlated with obesity in men (eating out for lunch: OR=1.10, 95%CI: 1.02-1.18; skipping lunch: OR=1.36, 95%CI: 1.02-1.80) while skipping lunch was positively associated with obesity (OR=1.47, 95%CI:1.07-2.02) in women. No statistical association was noticed between eating out for lunch and obesity in women, with OR=0.86 (95%CI: 0.73-1.00). Both eating out for dinner and skipping dinner were positively correlated with obesity in men, with eating out for lunch as OR=1.19 (95%CI: 1.06-1.34) and skipping dinner as OR=1.89 (95%CI: 1.07-3.33). Avoid dinner was positively associated with obesity in women, with OR=1.64 (95%CI: 1.02-2.63). Women who ate out for dinner showed lower risk of obesity than those who ate at home with OR=0.74 (95%CI: 0.59-0.94). Conclusions: Different eating behaviors were seen in Chinese adults, with the highest proportion of eating out for lunch and the lowest proportion for dinner. Both eating out for lunch and dinner appeared risk factors of obesity in men while avoid lunch or dinner were both associated with obesity in both sex.

[Risk factors and their interaction on cognitive impairment in the elderly in China: case-control study].

Objective: To investigate the association of apolipoprotein E (ApoE) genotype, sleep problem, olfaction problems, chronic constipation and their interactions on cognitive impairment in the elderly aged 60 and above. Methods: A stratified multi-stage cluster sampling was used in 6 provinces (autonomous administrative regions and municipalities) to select the sample. 1 300 cases with cognitive impairment and 2 600 controls without cognitive impairment were recruited and matched according to their age, gender and resident area in a 1∶2 case-control study. A total of 3 501 people were included after data cleaning. Chi-square test and conditional logistic regression model were used for univariate analysis, multivariate analysis and interaction analysis. Results: ApoE carrying ε4 genotypes, sleep problems, smell disorders, constipation is independent risk factors of cognitive impairment in the elderly (OR=1.44, 1.65, 2.26, 2.13, P<0.001). The additive interaction between ApoE genotype and olfaction change was statistically significant [AP=0.45(95%CI: 0.13- 0.77), S=2.37 (95%CI: 1.08-5.24)]. The interaction between other factors with cognitive impairment was not found to be statistically significant. The above results were adjusted for occupation, tea drinking, neighborhood interaction, social activities, physical exercise, reading books and newspapers, playing cards and mahjong, memory changes and hypertension, diabetes, stroke. Conclusions: ApoE genotype, sleep problems, olfaction problems, and chronic constipation are risk factors for cognitive impairment in people 60 and older. There is a synergistic interaction effect between ApoE genotype and olfaction problems on cognitive impairment in the elderly over 60 years old.

[Study of the prevalence and disease burden of chronic disease in the elderly in China].

Objective: To understand the prevalence and disease burden of major chronic diseases in the elderly in China and provide scientific basis for the prevention and control of chronic diseases and for the rational allocation of health resources. Methods: We analyzed the prevalence of chronic diseases in residents aged ≥60 years in China by using national and provincial surveillance data of chronic diseases and related risk factors in China. We conducted the analysis on the burden of chronic diseases in the elderly in China by using the data of global burden of disease. Results: The prevalence rates of hypertension, diabetes and hypercholesterolemia were 58.3%, 19.4% and 10.5% respectively in residents aged ≥60 years in China. Up to 75.8% of the residents aged ≥60 years had at least one chronic disease. The prevalence rate was higher in women than in men, higher in urban area than in rural area. With the increase of age, the prevalence rate of chronic diseases also increased. The top three chronic diseases with heavy disease burden in residents aged ≥70 years were stroke, myocardial infarction, cancer and chronic obstructive pulmonary disease. Conclusion: The prevalence of major chronic diseases in the elderly is high with three quarters of the elderly suffering from at least one chronic disease, and the burden of chronic diseases is increasing.

[Medical treatment seeking behaviors and its influencing factors in employed floating population in China].

Objective: To understand medical treatment seeking behaviors and its influencing factors in employed floating population in China and provide evidence for the development of health service policies for floating population. Methods: Data were from the national chronic disease and risk factor surveillance (floating population part) in 2012. Floating population were selected through multistage clustering sampling stratified by industries in 170 counties and districts from 31 provinces (autonomous regions, municipality directly under the central government) and Xinjiang Production and Construction Corps in the mainland of China. Information on demographic basic information, health status and health seeking behaviors six months before the investigation were collected through face-to-face questionnaire interview. The people aged 18-59 who had physical discomfort in the past six months was analyzed. After complex weighted analysis, multinomial logistic regression model was used to analyze the health seeking behavior and its influencing factors in the employed floating population. Results: A total of 11 134 suitable people aged 18-59 years were included in the study. The number and proportion of the people seeking medical treatment, having self-treatment and having no treatment were 4 950 (44.5%), 3 880 (34.8%) and 2 304 (20.7%), respectively. Multinomial logistic regression analysis showed that women were 1.275 times (95%CI: 1.100-1.477) more likely to seek medical treatment compared with men. The medical treatment seeking rates of floating population in the eastern, central and western areas were 2.153 times (95%CI: 1.669-2.777), 2.310 times (95%CI:1.777-3.002), 2.177 times (95%CI: 1.695-2.796) higher than that of floating population in northeastern area. In terms of seeking treatment, the proportion of the floating population with annual income of more than 25 000 yuan was 1.255 times (95%CI: 1.088-1.448) higher than that of the floating population with annual income of 25 000 yuan or less than 25 000 yuan. The proportion of the floating population with severe physical discomfort within the past six months was 8.076 times (95%CI: 6.091-10.707) higher than that of the floating population without severe physical discomfort and the proportion of the floating population who participated in medical insurance in both original living places and current living places was 1.566 times (95%CI: 1.250-1.961) higher than that of the floating population who did not participate in medical insurance in two places. The incidence ratio of medical care seeking and self-treatment in new generation of floating population was 1.369 (95%CI: 1.157-1.619) and 1.240 (95%CI: 1.042-1.475) compared with old generation of floating population. Compared with the widowed/divorced/separated, the incidence ratio of medical treatment seeking and self-treatment for the married/cohabited was 1.590 (95%CI: 1.057-2.391) and 1.815 (95%CI: 1.209-2.725). The more severe physical discomfort, the higher level medical institutions they chose (P<0.05). Conclusions: The treatment rate in medical institutions of employed floating population was low in China. Gender, generation of floating population, marital status, area, annual income, severity of physical discomfort in past six months and the way to participate in medical insurance were the main factors affecting the medical treatment seeking behaviors of employed floating population.

MEG3 is involved in the development of glaucoma through promoting the autophagy of retinal ganglion cells.

OBJECTIVE: In this study, we aimed at investigating whether MEG3 may be involved in the pathogenesis of glaucoma by regulating the autophagy of retinal ganglion cells (RGCs). MATERIALS AND METHODS: We used qRT-PCR to detect the expression of MEG3 in RGC-5s cell line under high hydrostatic pressure. RGC-5s were transfected with a lentiviral vector to achieve MEG3 overexpression or knockdown. The influence of overexpression or inhibition of MEG3 on cell proliferation and apoptosis was observed using CCK-8 test and flow cytometry. After overexpression of MEG3 and/or knockdown of MEG3 or Beclin-1, detection of the expressions of autophagy-related and apoptosis-related proteins was performed using Western blot. RESULTS: MEG3 expression level increased in RGC-5 cells under high hydrostatic pressure, while exogenously decreased MEG3 expression can reverse the impact of the high pressure on RGC-5 cells. Additionally, overexpression of MEG3 can improve Atg3 expression, promote cell apoptosis, inhibit cell proliferation, and enhance autophagy levels. Meanwhile, knockdown of Beclin-1 up-regulated Bcl-2 level. CONCLUSIONS: Upregulation of MEG3 is involved in the pathogenesis of glaucoma through promoting apoptosis of retinal ganglion cells, the mechanism of which may be related to the enhanced autophagy levels.

Neurorestorative effect of urinary bladder matrix-mediated neural stem cell transplantation following traumatic brain injury in rats.

Traumatic brain injury (TBI) is a leading cause of cell death and disability among young adults and lacks a successful therapeutic strategy. The multiphasic injuries of TBI severely limit the success of conventional pharmacological approaches. Recent successes with transplantation of stem cells in bioactive scaffolds in other injury paradigms provide new hope for the treatment of TBI. In this study, we transplanted neural stem cells (0.5x10(5) cells/µl) cultured in a bioactive scaffold derived from porcine urinary bladder matrix (UBM; 4 injection sites, 2.5µl each) into the rat brain following controlled cortical impact (CCI, velocity, 4.0 m/sec; duration, 0.5 sec; depth, 3.2mm). We evaluated the effectiveness of this strategy to combat the loss of motor, memory and cognitive faculties. Before transplantation, compatibility experiments showed that UBM was able to support extended proliferation and differentiation of neural stem cells. Together with its reported anti-inflammatory properties and rapid degradation characteristics in vivo, UBM emerged to be an ideal scaffold. The transplants reduced neuron/tissue loss and white matter injury, and also significantly ameliorated motor, memory, and cognitive impairments. Furthermore, exposure to UBM alone was sufficient to decrease the loss of sensorimotor skills from TBI (examined 3-28 days post-CCI). However, only UBMs that contained proliferating neural stem cells helped attenuate memory and cognitive impairments (examined 26-28 days post-CCI). In summary, these results demonstrate the therapeutic efficacy of stem cells in bioactive scaffolds against TBI and show promise for translation into future clinical use.

Adaptive-weighted cubic B-spline using lookup tables for fast and efficient axial resampling of 3D confocal microscopy images.

Confocal laser scanning microscopy has become a most powerful tool to visualize and analyze the dynamic behavior of cellular molecules. Photobleaching of fluorochromes is a major problem with confocal image acquisition that will lead to intensity attenuation. Photobleaching effect can be reduced by optimizing the collection efficiency of the confocal image by fast z-scanning. However, such images suffer from distortions, particularly in the z dimension, which causes disparities in the x, y, and z directions of the voxels with the original image stacks. As a result, reliable segmentation and feature extraction of these images may be difficult or even impossible. Image interpolation is especially needed for the correction of undersampling artifact in the axial plane of three-dimensional images generated by a confocal microscope to obtain cubic voxels. In this work, we present an adaptive cubic B-spline-based interpolation with the aid of lookup tables by deriving adaptive weights based on local gradients for the sampling nodes in the interpolation formulae. Thus, the proposed method enhances the axial resolution of confocal images by improving the accuracy of the interpolated value simultaneously with great reduction in computational cost. Numerical experimental results confirm the effectiveness of the proposed interpolation approach and demonstrate its superiority both in terms of accuracy and speed compared to other interpolation algorithms.

An automatic segmentation algorithm for 3D cell cluster splitting using volumetric confocal images.

With the rapid advance of three-dimensional (3D) confocal imaging technology, more and more 3D cellular images will be available. Segmentation of intact cells is a critical task in automated image analysis and quantification of cellular microscopic images. One of the major complications in the automatic segmentation of cellular images arises due to the fact that cells are often closely clustered. Several algorithms are proposed for segmenting cell clusters but most of them are 2D based. In other words, these algorithms are designed to segment 2D cell clusters from a single image. Given 2D segmentation methods developed, they can certainly be applied to each image slice with the 3D cellular volume to obtain the segmented cell clusters. Apparently, in such case, the 3D depth information with the volumetric images is not really used. Often, 3D reconstruction is conducted after the individualized segmentation to build the 3D cellular models from segmented 2D cellular contours. Such 2D native process is not appropriate as stacking of individually segmented 2D cells or nuclei do not necessarily form the correct and complete 3D cells or nuclei in 3D. This paper proposes a novel and efficient 3D cluster splitting algorithm based on concavity analysis and interslice spatial coherence. We have taken the advantage of using the 3D boundary points detected using higher order statistics as an input contour for performing the 3D cluster splitting algorithm. The idea is to separate the touching or overlapping cells or nuclei in a 3D native way. Experimental results show the efficiency of our algorithm for 3D microscopic cellular images.

3D boundary extraction of confocal cellular images using higher order statistics.

In recent years, cell biologists have benefited greatly from using confocal microscopy to study intracellular organelles. For high-level image analysis, 3D boundary extraction of cell structure is a preliminary requisite in confocal cellular imaging. To detect the object boundaries, most investigators have used gradient/Laplacian operator as a principal tool. In this paper we propose a higher order statistics (HOS) based boundary extraction algorithm for confocal cellular image data set using kurtosis. After the initial pre-processing, kurtosis boundary map is estimated locally for the entire volume using a cubic sliding window and subsequently the noisy kurtosis value is removed by thresholding. Voxels having positive kurtosis value with zero-crossing on its surface are then identified as boundary voxels. Typically used in signal processing, kurtosis for 3D cellular image processing is a novel application of HOS. Its reliable and robust nature of computing makes it very suitable for volumetric cellular boundary extraction.

Adaptive correction technique for 3D reconstruction of fluorescence microscopy images.

Recent advances in high-resolution imaging have provided valuable novel insights into structural relationships within cells and tissues both in vitro and in vivo. An analysis of this kind is regularly done by optical sectioning using either confocal or deconvolution microscopy. However, the reconstruction of 3D images suffers from light scattering and absorption with increasing depth by finite transparency of the used media. Photobleaching of fluorochromes has been especially troublesome and often the only remedy for loss of signal during optical sectioning is to reduce the number of sections. This causes disparities in the x-y and z dimensions of voxels, which lead to vertical distortion of the original stack of images and necessitates interpolation. Interpolation is necessary to fill up the gaps between consecutive sections in the original image stack to obtain cubic voxels. The present manuscript describes a novel method for adaptive compensation of attenuation of light intensity in stacks of fluorescence microscopy images that is based on a physical model of light attenuation. First, we use a fast interpolation technique to generate a cubic voxel-based volume stack with the aid of a contribution look up table. With the contribution look up table, multiple calculations are avoided, which substantially reduces the computational time without compromising the accuracy of the restoration procedure. Second, each section within the resulting volume is processed to rectify its intensity values that have been altered due to photobleaching and scattering and absorption. The method allows to define the last good section in the stack and the correction is then done automatically.

An automatic method for identifying appropriate gradient magnitude for 3D boundary detection of confocal image stacks.

Gradients play an important role in 2D image processing. Many edge detection algorithms are gradient-based. We are interested in 3D boundary detection which can be considered as an extension of 2D edge detection in 3D space. In this paper, an algorithm to automatically and quantitatively measure the suitability of gradient magnitudes in detection of 3D boundary points of confocal image stacks is presented. A Measurement Function is defined to evaluate the suitability of each gradient magnitude chosen to be the threshold for 3D boundary detection. The application of Gauss's Divergence Theorem provides a solution to calculate the Measurement Function numerically. The gradient magnitude at which the maximum of the Measurement Function is achieved can be utilized as the most appropriate threshold for gradient-based boundary detection and other operations like volume visualization.