The effects of capsinoids supplementation on body composition and anthropometric measures: A systematic review and dose-response meta-analysis of randomized controlled trials

BACKGROUND & AIMS

The present systematic review and meta-analysis was conducted to investigate the effects of capsinoids on body mass index (BMI), body weight (BW), waist circumference (WC), waist-hip ratio (WHR), fat mass (FM), fat-free mass (FFM), visceral fat area (VFA), and percentage body fat (PBF).

METHODS

Four databases were searched from inception to November 2020 using relevant keywords. All clinical trials investigating the effects of capsinoids supplementation on body composition and anthropometric measures were retained.

RESULTS

Overall, 19 effect sizes and 13 trials with a total sample size of 838 participants were included. Capsinoids supplementation had no effect on BW (P = 0.230), BMI (P = 0.182), WC (P = 0.611), FM (P = 0.946), FFM (P = 0.917), WHR (P = 0.599), VFA (P = 0.836), and PBF (P = 0.973). Findings from subgroup analysis revealed a significant reduction in BW in trials conducted on overweight participants, and lasted ≥12 weeks, However, no significant non-linear associations were found between capsinoids supplementation dosage and study duration with both BW (For dosage: P_{non-linearity} = 0.527, for duration: P_{non-linearity} = 0.410) and BMI (For dosage: P_{non-linearity} = 0.308, for duration: P_{non-linearity} = 0.578).

CONCLUSION

Capsinoids supplementation has no significant effect on obesity indicators. However, capsinoids in trials conducted on overweight participants, and lasted ≥12 weeks may have a significant and modest reduction in BW. Well-designed RCTs with larger sample size and longer duration are needed to confirm these results.

The effects of chromium supplementation on blood pressure: a systematic review and meta-analysis of randomized clinical trials

Results of studies on the effect of chromium supplementation on blood pressure (BP) are contradictory. The purpose of the current study was to carry out a meta-analysis on the effects of chromium supplementation on systolic blood pressure (SBP) and diastolic blood pressure (DBP). We conducted a systematic literature search of PubMed, SCOPUS, Cochrane Library, Web of Science, and Embase databases from inception up to July 2020 for randomized controlled trials (RCTs) that evaluate the impacts of chromium on SBP and DBP. A random-effects model was used to compute weighted mean differences (WMDs) with 95% confidence intervals (CIs). Heterogeneity was determined by I² statistics and the Cochrane Q test. Sensitivity analysis was performed by eliminating each study one by one and recalculating the pooled effect. Ten studies comprising a total of 624 subjects were included in our meta-analysis. Chromium supplementation did not significantly change SBP (WMD: -0.642: 95% CI: (-2.15, 1.30) mmHg; p = 0.312; I² = 12.7%) and DBP (WMD: -0.10; 95% CI: (-1.39, 1.18) mmHg; p = 0.070; I² = 37.6%). Subgroup analysis based on dose and duration of chromium supplementation also did not significantly change the mean of SBP and DBP. The present meta-analysis of RCTs did not show the beneficial effects of chromium supplementation on BP in adults.

The association between meal specific low carbohydrate diet score and cardiometabolic risk factors: A cross-sectional study of Iranian adults

BACKGROUND AND AIM

Since evidence regarding low-CHO diet and cardiometabolic risk factors is controversial, this study aimed to assess the relation between low-CHO diet score and metabolic syndrome (MetS) and cardiometabolic risk factors among a group of Iranian adults.

METHODS

This cross-sectional study was conducted with 840 subjects with the age range of 20-65 years. Dietary intakes were assessed by completing three 24-hour recalls. Total, animal- and vegetable-based low-CHO diet score were calculated. We used logistic regression with different models to determine whether there were relationships between low-CHO diet score and MetS and MetS components.

RESULTS

We found that there was no significant association between low-CHO diet, animal-based and vegetable-based low-CHO diet scores and risk of MetS in three meals. Except for the animal-based low-CHO diet score, which was significantly associated with general obesity at lunch meal (OR: 1.17, 95% CI: 0.76-1.82, P = .03). There were a significant association between low-CHO diet and high-density lipoprotein cholesterol (HDL-C) levels in lunch meal (OR: 1.50, 95% CI: 1.06-2.14, P = .03). Vegetable-based low-CHO diet score was associated with a lower risk of elevated TG in lunch meal in the fully adjusted model (OR: 0.59, 95% CI: 0.39-0.90, P = .04).

CONCLUSION

Diets with lower amounts of carbohydrate and higher contents of fat and protein were not significantly associated with the risk for MetS in Iranian adults. Only animal-based low-CHO diet score was significantly associated with general obesity at lunch meal.

Food Quality Score and Risk of Breast Cancer among Iranian Women: Findings from a Case Control Study

The quality of foods we consume may be an important risk factor for breast cancer (BrCa); however, relations between quality of food metrics and BrCa risk have not been systematically investigated. The purpose of this study was to examine the association between food quality score (FQS) by assessing the intake of healthy and unhealthy food and the odds of (BrCa) among Iranian women. This hospital-based case-control study was carried out on 150 women with pathologically confirmed breast cancer within the past three months and 150 healthy controls that were age-match from the Cancer Research Center, Imam Khomeini hospital, Iran. Participants were interviewed to obtain data relating to diet (using a 147-item validated FFQ) and BrCa risk factors. We found a significant association between adherence to the FQS and odds of breast cancer in the fully adjusted model (OR: 0.58; P = 0.04) and in premenopausal women in the fully adjusted model (OR: 0.45; P = 0.02); however, we did not observe any association between postmenopausal women in the adjusted model (OR: 0.76; P = 0.5). We also failed to observe any association between healthy (p = 0.3) and unhealthy subgroups (p = 0.3) of FQS. Our findings suggest that adherence to FQS may be associated with an increased risk of breast cancer in crude and adjusted models in overall and premenopausal women. However, we did not see any association between FQS and BrCa risk in postmenopausal women. Prospective cohort studies are needed to confirm these findings.Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.1957136 .

Dietary Carbohydrate Quality and Quantity and Risk of Breast Cancer among Iranian Women

OBJECTIVE

This study investigated the association between quality and quantity of carbohydrate by assessing low carbohydrates diet score (LCDS), carbohydrate quality score (CQI), glycemic index (GI), dietary glycemic load (GL), and dietary carbohydrate intake, and risk of breast cancer (BrCa) among Iranian women.

METHODS

This hospital-based case-control study was carried out in the Cancer Research Center of Imam Khomeini hospital, Iran. We included One hundred and fifty newly diagnosed BrCa cases and one hundred and fifty healthy controls in this study. Socio-demographic and dietary data and anthropometric measures were recorded.

RESULTS

We found that a higher CQI than a lower score was associated with a decrease in odds of BrCa (P = 0.04). After adjusting for potential confounders, we observed that CQI was not associated with BrCa development (P = 0.05). An increase in odds of BrCa among women in the highest tertiles of GL (P = 0.12), GI (P = 0.48), and dietary carbohydrate intake (P = 0.06) was seen, which was not statistically significant. There was also a non-significant lower chance of having BrCa with adherence to the LCDS (P = 0.09).

CONCLUSION

Our findings suggest that CQI was not related to BrCa risk among Iranian women. This relation deserves to be investigated in prospective studies.

The association between dietary acid load with cardiometabolic risk factors and inflammatory markers amongst elderly men: A cross-sectional study

BACKGROUND

Existing epidemiological data on dietary acid load and cardiovascular disease (CVD) are controversial. There is no literature evaluating the association between dietary acid load (DAL) with cardiometabolic risk factors and inflammatory markers in elderly.

OBJECTIVE

To evaluate the association between DAL and cardiometabolic risk factors amongst Iranian elders.

METHOD

A cross-sectional study was completed using 357 Iranian elders above >60 years of age. Anthropometric, clinical, and biochemical measurements were performed. Dietary intake was assessed using a validated and reliable food frequency questionnaire. DAL was estimated using the Potential Renal Acid Load (PRAL) score, Net Endogenous Acid Production (NEAP) and the Net Endogenous Acid Excretion (NAE) score. Metabolic syndrome (MetS) was defined according to the ATP-III criteria. Multivariable-adjusted odds ratios (ORs) of CVD risk factors were estimated using logistic regression.

RESULTS

After adjustment for confounders, a higher PRAL score was associated with higher odds of hypertriglyceridemia (OR: 2.28, 95% CI: 1.15, 4.50). We also observed that the NEAP score was positively associated with MetS (OR: 17.2, 95% CI: 2.34, 127). Finally, there was a positive association between NAE and lipid accumulation product (LAP) (OR: 1.81, 95% CI: 1.04, 3.17) and hypertriglyceridemia (OR: 2.46 95% CI: 1.22, 4.95).

CONCLUSION

Men with higher DAL scores had a higher risk of MetS, hypertriglyceridemia and LAP. Our findings suggest that further prospective studies are required to appraise DAL-CVD risk factors in populations with varying dietary patterns.

Association of Vitamin D status with Visceral Adiposity Index and Lipid Accumulation Product Index among a Group of Iranian People

There is a growing body of evidence linking vitamin D and its antiadipogenic activity with body composition. The aim of this study was to investigate the association between vitamin D levels, visceral adiposity index (VAI), and lipid accumulation product index among a group of Iranian people. This cross-sectional study was conducted with 270 Iranian adults. Body composition was measured via bio-impedance analysis. The 25-hydroxyvitamin D [25(OH)D] was also measured using the enzyme-linked immunosorbent assay method. The VAI and lipid accumulation product index were calculated. Multiple linear and logistic regression after controlling for confounder was used to report the results. Multiple linear regression showed that serum 25(OH)D levels were positively correlated with age (crude: β ± standard error [SE] = 0.23 ± 0.06, p ≤ 0.001; model I: β ± SE = 0.18 ± 0.05, p = 0.002) and percent body fat (crude: β ± SE = 0.10 ± 0.04, p = 0.02). Binary logistic regression analysis showed a higher chance of greater percent body fat and lipid accumulation product index in the crude model (odds ratio [OR], 2.05; 95% confidence interval [CI], 1.13–3.72 for percent body fat and OR, 2.07; 95% CI, 1.14–3.76 for lipid accumulation product index), which disappeared after adjusting for covariates. Adults with higher vitamin D levels had higher scores of percent body fat and lipid accumulation product index. More longitudinal studies are needed to confirm these results.

The association between healthy lifestyle score with cardiorespiratory fitness and muscle strength

OBJECTIVE

The association of individual behaviours such as diet, tobacco use, body mass index (BMI) and physical activity have been investigated separately in relevance to cardiorespiratory fitness (CRF) and muscle strength. The purpose of this study is to investigate the combined association of the four mentioned lifestyle factors with cardiorespiratory fitness and muscle strength.

METHODS

This cross-sectional study was conducted on 271 Iranian adults, aged 18-70 years. We developed a healthy lifestyle score (HLS) that ranged from 0 to 103 (higher score reflecting better adherence to healthier lifestyle) and included four lifestyle behavioural components (diet, physical activity, smoking and BMI). The relationship between HLS, CRF and muscle strength was determined using linear and non-linear regression analysis.

RESULTS

HLS score was not significantly associated with VO_2max (mL/kg/min) P = .43; VO_2max (L min) P = .14; VO_2max (LBM) (P = .79) and mean muscle strength (MMS) (kg) (P = .11), muscle strength of right hand (MSR) (kg) (P = .10) and muscle strength of left hand (MSL) (kg) (P = .16) in the unadjusted model. After adjustment for potential confounders, we found a significant association between HLS and Vo_2max (L/min), MMS (kg), MSR (kg) and MSL (kg) (P < .001 for all). Also HLS and MMS (r = .06, P = .31), MSR (r = .07, P = .25), MMS (r = .05, P = .39), VO_2max (mL/kg/min) (r = .01, P = .77), VO_2max (L min) (r = .05, P = .35) and VO_2max (LBM) (r = .002, P = .91) have no statistically significant linear relationship.

CONCLUSION

Adherence to healthy lifestyle may be associated with increased CRF and muscle strength after adjusting for potential confounding variables.

Circulating levels of metabolic biomarkers of site-specific and sex-specific arterial calcification in the multi-cohort BBMRI setting

Background/Introduction

Increasing evidence shows that greater arterial calcification leads to an elevated risk of atherosclerotic cardiovascular disease. Risk factors and prognosis of arterial calcification seems to vary per site and between women and men. However, the underlying biological mechanisms of site-specific calcification and the associated sex differences are largely unknown. Within the BBMRI framework, we performed a multi-cohort study on the associations of the circulating levels of metabolic biomarkers with arterial calcification at various sites among women and men.

Purpose

To examine the associations of the circulating levels of metabolic biomarkers with coronary artery (CAC), aortic arch (AAC) and the aortic valve (AVC) calcifications among women and men.

Methods

We included a total of 1,114 participants from the population-based Rotterdam Study and 390 from the Leiden Longevity Study. Study populations were comparable concerning study characteristics. Blood samples were used to determine a wide range of plasma metabolic biomarkers by proton nuclear magnetic resonance (NMR). Participants underwent non-contrast computed tomography to quantify the volume of CAC, AAC, and AVC. Linear regression modelling adjusted for relevant covariates was used to assess the associations of 166 metabolic biomarkers with CAC, AAC, and AVC. Correction for multiple testing was based on 33 independent metabolic biomarkers (p-value 0.05/33 = 1.5 x 10–3).

Results

Mean (standard deviation - SD) age was 69.5 (6.8) and 780 (52.0%) of the study population were women. One SD increase in concentration of a1-acid glycoprotein, was associated with a 0.10 SD (standard error (SE) = 0.03) increase in AAC (p-value = 9.5x10–4) in the overall population (Figure 1). When we stratified our analyses based on sex, this association was mainly driven by men [beta (SE) per SD: 0.12 (0.05), p-value = 0.007]. Moreover, an SD increase in acetate was associated with a 0.14 SD (SE = 0.04) decrease in CAC (p-value 1.7x10–4) in women but not in men [beta (SE) per SD: −0.04 (0.03), p-value = 0.22] (Figure 1).

Conclusion(s)

Higher levels of circulating glycoproteins were associated with increased AAC in men. Moreover, lower levels of circulating acetate were associated with increased CAC in women. These results provide evidence for location-specific differences and sex-specific effects in the underlying biological mechanisms of atherosclerosis. Our findings carry the potential to contribute to the early detection of individuals at increased risk for developing atherosclerotic cardiovascular disease and to a better understanding of disease etiology.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was performed within the framework of the BBMRI Metabolomics Consortium funded by BBMRI-NL, a research infrastructure financed by the Dutch government through Netherlands Organisation for Scientific Research (NWO) (Grant Nos. 184.021.007 and 184033111). MK was supported by VENI grant (91616079) from The Netherlands Organization for Health Research and Development (ZonMw).

The Effect of Total Knee Arthroplasty on Hindfoot Alignment in Patients with Severe Genu Varum and Genu Valgum

Background

The maintenance of deformity in the ankle and hindfoot after correction of knee deformity following knee arthroplasty may cause abnormal tension in the knee and patient dissatisfaction. The aim of this study was to determine the effect of knee arthroplasty on the hindfoot alignment in patients with severe genu varum and valgum.

Methods

A total of 84 patients with primary osteoarthritis, were enrolled in the study. The knee deformity was measured using a long leg film before surgery. The long axial radiographic view of hindfoot was taken in the standing position for all patients, before and six months after surgery. Comparisons were made on changes in the hindfoot angles measured before and after surgery.

Results

A total of 84 patients with mean age of 62.28 ± 7.77 years, 77 (92%) and seven patients (eight percent) had knee varus and valgus deformity, respectively. In the knee varus group, the mean preoperative hindfoot angle was + 5.32 ± 6.12 ° (valgus) which was changed to - 0.25 ± 4.91 ° (varus) in the postoperative phase. In the knee valgus group, the mean pre and postoperative hindfoot angles were - 7.71 ± 7.06° (varus) and - 2.14 ± 5.92 ° (varus), respectively. The mean preoperative hindfoot angle in severe and very severe varus knee groups were + 5.45 ± 3.30 and + 5.28 ± 6.86 °, respectively. These angles were changed to + 0.21± 5.17 and -1.60 ± 3.89° six months after surgery, respectively. The mean preoperative hindfoot angle in severe and very severe valgus knee deformity groups were - 7.00 ± 4.69 and -8.66 ± 10.69 °, respectively. These angles were changed to - 2.00 ± 5.71 and - 2.33 ± 7.50 °after surgery, respectively. There was no significant difference between patients with severe and very severe deformity in terms of pre and post-operative hindfoot angle.

Conclusion

The hindfoot alignment is significantly corrected after knee arthroplasty. The severity of knee deformity does not correlate with the severity of the hindfoot deformity before and after surgery.

The effects of magnesium supplementation on obesity measures in adults: a systematic review and dose-response meta-analysis of randomized controlled trials

Previous studies reported inconsistent findings regarding the effects of magnesium supplementation on obesity measures. This study was done to quantify the effect of magnesium supplementation on body weight, Body Mass Index (BMI), Waist Circumference (WC), Body Fat (BF) percentage and Waist to Hip Ratio (WHR). Four online databases (Scopus, PubMed, Google Scholar and Cochrane library) were searched until March 2020 using relevant keywords. Random-effects model was used to pool effect sizes; Cochran's Q-test and I2 index assessed heterogeneity. Sensitivity analysis and Egger test were used to check the robustness of findings and the possibility of publication bias, respectively. Thirty-two RCTs including different dosage of magnesium (48-450 mg/d), and duration (6-24 weeks) were entered to this study. Magnesium supplementation resulted in a great reduction in BMI [Weighted Mean Difference (WMD): -0.21 kg/m², 95% CI: -0.41, -0.001, P = 0.048, I² = 89.5%, n = 22], which was mainly driven by the effect among those with magnesium deficiency, insulin resistance related disorders, and obesity at baseline. No significant change was observed in bodyweight, WC, BF percentage and WHR as compared to controls. However, the change in body weight, and WC was significant in subgroups of participants with insulin resistance related disorders, hypertension, obesity, magnesium deficiency at baseline, and females. We found a significant reduction in BMI following magnesium supplementation. The change in body weight and WC were evident in certain subgroups.

Association of SRD5A2 gene mutations with risk of hypospadias in the Iranian population

BACKGROUND

Hypospadias is one of the most common forms of congenital malformation of the male external genitalia worldwide. The ratio in the Iranian population is one in 250 live male births. The conversion of testosterone to dihydrotestosterone (DHT) in the presence of steroid 5α-reductase 2, which is encoded by SRD5A2 gene, plays an important role in the normal development of the male reproductive system.

METHODS

We examined whether SRD5A2 gene mutations (V89L and A49T polymorphisms) are associated with the risk of hypospadias in the Iranian population. We performed exons sequencing for SRD5A2 gene in 109 hypospadias patients.

RESULTS

We identified two new mutations in the subgroups of affected cases: including a substitution of the nucleotide T > A in the codon 73 [c.219T > A (p.Leu73_Ser74insHisPro)] and an insertion of an extra A nucleotide in the codon 77 [c.229insA* (p.Gly77*)]. Additionally, we performed PCR-RFLP for the two identified polymorphisms and revealed that V89L [OR = 5.8, 95% CI (3.8-8.8), p value < 0.001] and A49T [OR = 10.16, 95% CI (3.94-26.25), p value < 0.001] are significantly associated with hypospadias occurrence in patients. Our haplotype analysis further indicated that the Leu-Ala haplotype increases risk of hypospadias; conversely, the Val-Ala haplotype decreases the risk of hypospadias in the studied patients.

CONCLUSIONS

This study demonstrates that polymorphisms in the SRD5A2 gene could be considered as a risk factor for hypospadias disease emergence.

Preparation and characterization of a novel highly hydrophilic and antifouling polysulfone/nanoporous TiO2 nanocomposite membrane

In this research, novel ultrafiltration nanocomposite membranes were prepared by incorporating self-synthesized nanoporous titanium dioxide (NTiO2) nanoparticles into polysulfone. The surface of the nanoparticle was treated with a silane-based modifier to improve its distribution in the host polymer. Atomic-force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller, transmission electron microscopy, energy-dispersive x-ray spectroscopy, porosity and contact angle tests were conducted to characterize the properties of the particles as well as the fabricated nanocomposite membranes. The effects of the nanoparticle incorporation were evaluated by conducting ultrafiltration experiments. It was reported that the membrane pure water flux was increased with increasing NTiO2 loading owing to the high porosity of the nanoparticles embedded and/or formation of enlarged pores upon addition of them. The antifouling capacity of the membranes was also tested by ultrafiltration of bovine serum albumin fouling solution. It was found that both water flux and antifouling capacity tended to reach desired level if the NTiO2 added was at optimized loading.

Solvothermal synthesis of nanoporous TiO2: the impact on thin-film composite membranes for engineered osmosis application

In the current study, the impact of self-synthesized nanoporous titanium oxide (NT) on the morphology, performance and fouling of a polyamide (PA) thin-film composite (TFC) membrane was investigated when the membrane was applied for engineering osmosis (EO). The nanoporous structure and the spindle-like shape of NT were revealed through transmission electron microscopy (TEM), while the AATPS modification of NT was verified by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The results of x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) confirmed the presence of modified NT (mNT) in the PA dense active layer of the TFC membrane. The outgrowth of the 'leaf-like' structure, upon mNT loading, at the surface of the PA layer was observed by field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The TFC membrane prepared with 0.05 wt% mNT loading in the organic phase showed the water flux of 26.4 l m(-2) h(-1) when tested in the forward osmosis (FO) mode using 0.5M and 10 mM NaCl solution as the draw and feed solution, respectively. Moreover, the TFC-mNT membrane also demonstrated an intensified antifouling property against organic foulant during FO application and it was possible to retrieve the initial water flux almost completely with a simple water-rinsing process.

The effect of maternal hypothyroidism on cardiac function and tolerance to ischemia-reperfusion injury in offspring male and female rats

PURPOSE

Accumulating evidence indicates that intrauterine evolution disturbance can contribute to myocardial ischemia reperfusion (IR) injury; in addition, thyroid hormones (THs) have a crucial role in the development of different systems during fetal life. The aim of this study was to determine the effect of TH deficiency during fetal life on tolerance of isolated heart to ischemia during adulthood in both genders.

METHODS

Hypothyroidism was induced in pregnant Wistar rats by administrating 0.025 % 6-propyl-2-thiouracil in drinking water throughout pregnancy. Offspring of rats with maternal hypothyroidism (MH) and control groups were tested in adulthood. Isolated hearts were perfused with Langendorff setup and exposed to 30 min of ischemia, followed by 45 min of reperfusion. Baseline values of the left ventricular end-diastolic pressure (LVEDP), left ventricular developed pressure (LVDP), heart rate (HR), and peak rates of positive and negative changes in left ventricular pressure (±dp/dt) were recorded.

RESULTS

In the MH groups the baseline levels of LVDP (male: 23 %, female: 33 %), HR (male: 31 %, female: 26 %), and ±dp/dt were significantly (p < 0.01) lower, compared to controls. After ischemia, hearts from male rats with MH had less tolerance to IR injury as assessed in terms of reductions in recovery of hemodynamic parameters compared to controls, while in female rats there were no significant differences between MH and controls.

CONCLUSIONS

MH decreases hemodynamic parameters in the heart of both male and female offspring in adulthood; in addition, hearts of male rats with MH show less tolerance to ischemia, compared to those of females.

Synthesis and characterization of novel thin film nanocomposite reverse osmosis membranes with improved organic fouling properties for water desalination

Incorporation of HNTs into PA layer improved not only the structural and separation characteristics of composite membrane but also its antifouling properties.

Nonlinear analysis of anesthesia dynamics by Fractal Scaling Exponent

The depth of anesthesia estimation has been one of the most research interests in the field of EEG signal processing in recent decades. In this paper we present a new methodology to quantify the depth of anesthesia by quantifying the dynamic fluctuation of the EEG signal. Extraction of useful information about the nonlinear dynamic of the brain during anesthesia has been proposed with the optimum Fractal Scaling Exponent. This optimum solution is based on the best box sizes in the Detrended Fluctuation Analysis (DFA) algorithm which have meaningful changes at different depth of anesthesia. The Fractal Scaling Exponent (FSE) Index as a new criterion has been proposed. The experimental results confirm that our new Index can clearly discriminate between aware to moderate and deep anesthesia levels. Moreover, it significantly reduces the computational complexity and results in a faster reaction to the transients in patients' consciousness levels in relations with the other algorithms.

Dimensional characterization of anesthesia dynamic in reconstructed embedding space

The depth of anesthesia quantification has been one of the most research interests in the field of EEG signal processing and nonlinear dynamical analysis has emerged as a novel method for the study of complex systems in the past few decades. In this investigation we use the concept of nonlinear time series analysis techniques to reconstruct the attractor of anesthesia from EEG signal which have been obtained from different hypnotic states during surgery to give a characterization of the dimensional complexity of EEG by Correlation Dimension estimation. The dimension of the anesthesia strange attractor can be thought of as a measure of the degrees of freedom or the ;complexity' of the dynamics at different hypnotic levels. The results imply that for awaked state the correlation dimension is high, On the other hand, for light, moderate and deep hypnotic states these values decrease respectively; which means for anesthetized situation we expect lower correlation dimension.

Optimization of MPEG-2 SNR scaleable codecs

It is shown how the signal-to-noise (SNR) scaleable coder can benefit from optimizing quantified discrete cosine transform (DCT) coefficients, in a rate-distortion context, in order to reduce bit-rate overheads. The technique is based on adjusting the quantized coefficients rather than dropping them, since the former gives finer control over rate-distortion trade-offs. The widely used Lagrangian optimization technique is then applied to arrive at the optimally adjusted coefficients block. We show that such an optimization is very efficient for the second layer, but has little effect on the base layer.

A successive approximation vector quantizer for wavelet transform image coding

A coding method for wavelet coefficients of images using vector quantization, called successive approximation vector quantization (SA-W-VQ) is proposed. In this method, each vector is coded by a series of vectors of decreasing magnitudes until a certain distortion level is reached. The successive approximation using vectors is analyzed, and conditions for convergence are derived. It is shown that lattice codebooks are an efficient tool for meeting these conditions without the need for very large codebooks. Regular lattices offer the extra advantage of fast encoding algorithms. In SA-W-VQ, distortion equalization of the wavelet coefficients can be achieved together with high compression ratio and precise bit-rate control. The performance of SA-W-VQ for still image coding is compared against some of the most successful image coding systems reported in the literature. The comparison shows that SA-W-VQ performs remarkably well at several bit rates and in various test images.

On the performance of linear phase wavelet transforms in low bit-rate image coding

The behavior of linear phase wavelet transforms in low bit-rate image coding is investigated. The influence of certain characteristics of these transforms such as regularity, number of vanishing moments, filter length, coding gain, frequency selectivity, and the shape of the wavelets on the coding performance is analyzed. The wavelet transforms performance is assessed based on a first-order Markov source and on the image quality, using subjective tests. More than 20 wavelet transforms of a test image were coded with a product code lattice quantizer with the image quality rated by different viewers. The results show that, as long as the wavelet transforms perform reasonably well, features like regularity and number of vanishing moments do not have any important impact on final image quality. The influence of the coding gain by itself is also small. On the other hand, the shape of the synthesis wavelet, which determines the visibility of coding errors on reconstructed images, is very important. Analysis of the data obtained strongly suggests that the design of good wavelet transforms for low bit-rate image coding should take into account chiefly the shape of the synthesis wavelet and, to a lesser extent, the coding.

Layered image coding using the DCT pyramid

A block-based subband image coder that exploits the ability to perform decimation in the discrete cosine transform (DCT) domain to effect a pyramidal data structure is described. The proposed "DCT pyramid" has a distinct feature of improved image rendition properties without the associated blocking artifacts at low bit-rates.

Modeling and subjective assessment of cell discard in ATM video

Measurements of subjective picture impairment as a function of network loading in a simulated ATM network are reported. The simulation indicated that cells tend to be discarded in bursts, the frequency and severity of which can be related to the loading by a threshold model. The effect of the discards on broadcast-style video, coded using a single-layer H.261-type method, was found to be a function of scene content and movement at the instant of occurrence. If the visibility of cell discards is maintained at or below threshold in worst-case scenes, the study indicated that network loadings around 55% for a multiplex of 16 video sources and around 70% for a multiplex of 48 video sources are achievable.