Objective Quality Parameters Research Articles

The impact of forced awakening on morning blood pressure surge

BackgroundPoor sleep quality can cause an increase in morning blood pressure surge (MBPS), an independent risk factor of cardiovascular disease (CVD) events. Awakening induced by external factors such as alarm clocks, may also contribute to increased MBPS. ObjectivesTo (1) compare the MBPS and sleep quality parameters between natural and forced awakenings and (2) examine the potential impact of forced awakening on MBPS, independent of sleep quality. MethodsThirty-two healthy adults participated in this pilot study, which included one night of natural awakening and one night of forced awakening (i.e., sleep was interrupted by an alarm after five hours). Objective and self-reported sleep quality parameters were measured using a multisensory wristband and sleep diaries, respectively, and beat-to-beat blood pressure variability was assessed using a continuous blood pressure monitor. Analyses included a paired t-test (objective 1) and linear mixed models (objective 2). ResultsParticipants predominantly consisted of young, healthy, and highly educated Asian adults. During the night of sleep with forced awakening, significantly higher MBPS, lower objective wakefulness after sleep onset, and lower self-reported sleep latency were observed, compared to the night with natural awakening. Forced awakening was significantly associated with increased MBPS after controlling for age, sex, mean arterial pressure, and sleep quality. ConclusionsForced awakening may significantly increase MBPS, consequently heightening the risk of CVD events. Study findings should be validated in a larger sample. Further research is also warranted to examine the impact of forced awakening on MBPS in individuals with CVD.

Effect of a nutraceutical combination on sleep quality among people with impaired sleep: a randomised, placebo-controlled trial

In this randomised, placebo-controlled trial, adults with impaired sleep (Pittsburgh Sleep Quality Index ≥ 5) were randomly assigned using a minimization algorithm to receive a formulation containing l-theanine plus lemon balm, valerian, and saffron extracts, or placebo, during 6 weeks. Objective sleep quality parameters were measured using an actigraphy device. We enrolled and randomised 64 individuals, 31 from the active group and 27 from the placebo group completed the 6 week follow-up. Mean sleep efficiency remained unmodified in the active group, and increased by 3% in the placebo group, the between-group difference in the change was not statistically significant (p = 0.49). Total sleep time also improved more with placebo (13.0 vs. 1.33 min, p = 0.66). Time wake after sleep onset (WASO) decreased more in the active group (4.6% vs. 2.4%), but the difference was not significant (p = 0.33). Mean PSQI decreased by 3.11 points (32.3%) in the active group, and by 3.86 points (39.5%) in the placebo group (p = 0.41). SF-36 increased more with placebo (+ 18.3 in active, + 32.1 in placebo, p = 0.68). Salivary cortisol remained unchanged in both groups. No serious adverse events were reported. Among adults with impaired sleep, a nutraceutical combination did not improve objective or subjective sleep parameters more than a placebo infusion.

Physical activity in the treatment of primary insomnia

Insomnia is commonplace in the general population. Poor sleep quality leads to various health dysfunctions and compromises the well-being of the affected individuals. Non-pharmacologic approaches should be considered the first-line treatment as suggested by various guidelines. Among others (e.g., sleep hygiene, cognitive-behavioral therapy, light therapy), appropriate physical activity seems to be promising in treating and preventing sleep disturbance development. We found that improvement in a particular objective and subjective sleep quality parameters may be attributed to appropriate physical activity. When further analyzing the activity, lightintensity aerobic exercises and resistance training reduced insomnia symptoms. High-intensity interval training also showed a positive effect on the improvement in depressive symptoms. Regarding mind-body practices, current evidence is insufficient to conclude. However, it was documented that stress, depression, and anxiety reduction, can improve well-being.

Potential of phytic acid in synergy with sodium chloride as a natural-borne preservative to inactivate Escherichia coli O157:H7 and inhibit natural microflora in fresh noodles at room temperature

The increase in consumer demand and the high cost of maintaining a cold chain during distribution emphasize the need for preservative technology to ensure the microbiological quality of fresh noodles with a moisture content of 32–40%. However, few studies have been conducted to increase the storage stability of fresh noodles by using a preservative with a significant inhibitory effect against microorganisms and/or minimizing the use of synthetic antimicrobial agents. This study aimed to propose a synergistic natural-borne antimicrobial that could interact with NaCl, an essential component of noodles, for extended preservation of fresh noodles at room temperature. NaCl (0–1.6% (w/w) based on the total weight of the noodle dough) and phytic acid (0–1.0% (v/w)) were applied to fresh noodles. The bactericidal effect on Escherichia coli O157:H7 and the inhibitory effect on the indigenous microflora were assessed within 21 days at 30 °C. After cooking fresh noodles, physicochemical/textural and sensory characteristics (whiteness, pH, water activity; hardness, adhesiveness, springiness, chewiness; appearance, odor, overall acceptance) were further evaluated as objective and subjective quality parameters. In fresh noodles preserved with 0.6% phytic acid and 1.6% NaCl, the E. coli O157:H7 population was eliminated below the detection limit (>5.8 log reduction; P < 0.05) within 4 days of storage. This preservative significantly inhibited (P < 0.05) the mesophilic bacterial and total yeast/mold counts naturally present in fresh noodles for 12 days, while the largest antimicrobial activity was observed in noodles supplemented with 1.0% phytic acid combined with 1.0–1.6% NaCl. Although the objective parameters were significantly affected by the preservatives, analysis of the subjective parameters demonstrated that all samples were slightly or moderately favored by the panelists (P > 0.05). Considering the normal range of objective parameters for fresh noodles, the optimal preservative was determined to be 0.6% phytic acid and 1.6% NaCl. This study suggests the potential use of phytic acid as a natural-borne preservative that combines with NaCl in fresh noodles and exerts a synergistic effect. The developed method is expected to be applicable to extending the shelf life of other grain-based foods containing NaCl as an essential ingredient.

Effects of raw and hydrolysed Nannochloropsis gaditana biomass included at low level in finishing diets for gilthead seabream (Sparus aurata) on fillet quality and shelf life

Numerous studies evaluating the effects of the incorporation of microalgae in feeds have reported favourable impacts on different physiological aspects of aquacultured fish. Although productivity is the major goal in terms of profitability in fish farming, qualitative aspects are gaining the attention of producers, given the relevance of quality attributes related to organoleptic parameters, proximal composition, and shelf life on the commercial value of fish. Indeed, microalgae are acknowledged for their richness in substances with potential positive effects on all those quality attributes. In this context, this study assesses the effects of finishing diets enriched with the microalga Nannochloropsis gaditana, either crude or enzymatically hydrolysed, on several quality parameters of gilthead seabream (Sparus aurata) fillets. Two inclusion levels (2.5 and 5%) of raw and enzymatically hydrolysed microalgal biomass were incorporated into diets, plus a microalgae-free control diet, and a 42-day feeding trial was carried out on fish of commercial size (approx. 500 g body weight). The influence of the experimental diets on fish biometry, fillet quality parameters, and shelf life was evaluated. The results indicate, overall, that microalgae-enriched diets yielded favourable, dose-dependent effects on several objective quality parameters of fillets, namely, improved fatty acid profile, reduced microbial counts, enhanced lipid oxidative status, and improved textural and skin colour attributes. Although the enzymatic pre-treatment of the microalgal biomass was expected to impact positively its functional effects on all quality parameters, however, no general trend was observed.

The Association between the Level of Advanced Glycation End Products and Objective Skin Quality Parameters

Advanced glycation end products (AGEs) represent an endogenously produced or exogenously derived group of compounds derived from nonenzymatic glycation. Recent experimental studies are suggesting that AGEs could play an important role in the skin's quality and its aging process. Hence, the aim of this study was to clinically evaluate the AGEs and skin quality parameters across different age groups in the general population. The study included 237 participants. Melanin, erythema, hydration, friction and transepidermal water loss (TEWL) were evaluated using noninvasive probes, while AGEs were evaluated using a skin autofluorescence reader. There was a significant positive correlation between AGEs and the amount of melanin (p < 0.001), erythema (p < 0.001) and TEWL (p < 0.001), while there was a significant negative correlation between AGEs and hydration (p < 0.001) and friction (p < 0.001). After dividing the sample into three groups depending on their age, in all three groups, there was a significant positive correlation between AGEs and the melanin count (p < 0.001) and TEWL (p < 0.001), while there was a significant negative correlation between AGEs and skin hydration (p < 0.001). Multiple linear regression analysis showed that the level of AGEs as a dependent variable retained a significant association with age (p < 0.001), melanin (p < 0.001), erythema (p = 0.005) and TEWL (p < 0.001) as positive predictors. Moreover, AGEs retained a significant association with skin hydration (p < 0.001) and friction (p = 0.017) as negative predictors. These outcomes imply that AGEs could be linked with the complex physiology of the skin and its aging process.

Quality of Vision After LASIK, PRK and FemtoLASIK: An Analysis Using the Double Pass Imaging System HD AnalyzerTM®.

PurposeAnalyze and compare the quality of vision of Photorefractive keratectomy (PRK), LASER in situ keratomileusis with mechanical microkeratome (LASIK) and femtosecond-assisted LASIK (FS-LASIK) using the double-pass imaging system HD AnalyzerTM®.SettingOphthalmology department of Centro Hospitalar Universitário do Porto (CHUPorto).DesignRetrospective, non-randomized, single center study.MethodsAnalysis of three equivalent groups of patients submitted to PRK, LASIK and FS-LASIK at our department. The objective quality of vision assessment included the objective scatter index (OSI), the modular transfer function cutoff frequency (MTF) and the predicted visual acuity within the 100% (PVA), 20% (PVA20) and 9% contrast levels (PVA9) that were evaluated at baseline, 1st week, 1 and 6 months after surgery.Results118 eyes were included: 40 underwent LASIK, 43 FS-LASIK and 35 PRK. The mean age was 30.6±4.6 years old and 56% were female. There was a significant impact concerning the type of procedure in the objective quality of vision analysis (Repeated measures ANOVA): the FS-LASIK group showed lower OSI values overtime [F(1,2)=4.566, p=0.012, OSI 0.83±0.53 (FS-LASIK) vs 0.87±0.47 (PRK) and 1.21±1.44 (LASIK)], higher MTF values [F(1,2)=6.569, p=0.002, MTF 40.17±8.33 vs 32.37±11.4 (PRK) and 30.26±10.28 (LASIK)], higher PVA 100% [F(1,2)=10.871, p<0.001], PVA 20% [F(1,2)=9.737, p<0.001] and PVA 9% [F(1,2)=6.335), p=0.003].ConclusionIn our study, FS-LASIK showed an excellent optical performance through the HD AnalyzerTM technology, with significantly lower OSI and higher MTF, PVA100, PVA20 and PVA9 values. According to our results, this procedure seems to be superior to PRK and LASIK regarding visual quality objective parameters.

Interior Sound Field Subjective Evaluation Based on the 3D Distribution of Sound Quality Objective Parameters and Sound Source Localization.

Controlling low frequency noise in an interior sound field is always a challenge in engineering, because it is hard to accurately localize the sound source. Spherical acoustic holography can reconstruct the 3D distributions of acoustic quantities in the interior sound field, and identify low-frequency sound sources, but the ultimate goal of controlling the interior noise is to improve the sound quality in the interior sound field. It is essential to know the contributions of sound sources to the sound quality objective parameters. This paper presents the mapping methodology from sound pressure to sound quality objective parameters, where sound quality objective parameters are calculated from sound pressure at each specific point. The 3D distributions of the loudness and sharpness are obtained by calculating each point in the entire interior sound field. The reconstruction errors of those quantities varying with reconstruction distance, sound frequency, and intersection angle are analyzed in numerical simulation for one- and two-monopole source sound fields. Verification experiments have been conducted in an anechoic chamber. Simulation and experimental results demonstrate that the sound source localization results based on 3D distributions of sound quality objective parameters are different from those based on sound pressure.

Is Sleep Associated with the S-Klotho Anti-Aging Protein in Sedentary Middle-Aged Adults? The FIT-AGEING Study.

Sleep and Klotho have both been closely related to the ageing process, both playing a substantial role in the endocrine and immune systems and, thereby, in oxidative stress and chronic inflammation. However, there are no studies elucidating the relationship between sleep and Klotho. Therefore, this study investigated the association of sleep quantity and quality with the shed form of the α-Klotho gene (S-Klotho plasma levels) in sedentary middle-aged adults. A total of 74 volunteers (52.7% women; aged 53.7 ± 5.1) were recruited for the present study. Objective sleep quality parameters (total sleep time (TST), wake after sleep onset (WASO), and sleep efficiency (SE)) were determined using a wrist-worn accelerometer over seven consecutive days, and the subjective sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI; higher scores indicate worse sleep quality). The S-Klotho plasma levels were measured in the ethylenediaminetetraacetic acid plasma using a solid-phase sandwich enzyme-linked immunosorbent assay. Objective sleep parameters were associated with the S-Klotho plasma levels only after including the age, fat mass percentage, and lean mass index as covariates. A direct relationship was observed between the subjective sleep quality (inverse of PSQI scores) and the S-Klotho plasma levels in sedentary middle-aged adults. Improving sleep quantity and quality could be considered an anti-aging therapeutic approach for the prevention, slowing, and even reversal of the physiological decline and degenerative pathologies that are certainly related to the aging process.

Road Noise Evaluation by Sound Quality Simulation Module

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;An objective evaluation of sound quality is a technical bridge connecting sound pressure level (SPL) and human auditory sensation. In this paper, an algorithm is proposed for calculating objective evaluation parameters of sound quality (including loudness, sharpness and articulation index), considering acoustic characteristics of human external ear, middle ear and inner ear to reflect auditory sensation. A sound quality simulation (SQS) module is coded according to the algorithm. The module is used for evaluating sound quality of road noise from an SUV in three steps. Firstly, interior noise is predicted by integrating finite-element method (FEM), hybrid FE-SEA method, and statistical energy analysis (SEA) for low frequency (20~315 Hz), medium frequency (315~500 Hz), and high frequency (&amp;gt;500 Hz) in 1/3 octave band, respectively. The predicted interior noise SPLs are compared with the measured results, with deviations less than 3dB in average. Secondly, the sound quality parameters are calculated using the predicted SPLs in the SQS module. The predicted and measured loudness, sharpness, and articulation index are compared, with average deviations less than 5%. Finally, the predicted interior noise is filtered by the SQS module in 1/3 octave band, to determine the dominant contribution bands for the sound quality parameters. Several optimized designs are implemented to optimize the sound quality parameters, and validated by experiments.&lt;/div&gt;&lt;/div&gt;

Assessment of long-term effects of the macroalgae Ulva ohnoi included in diets on Senegalese sole (Solea senegalensis) fillet quality

Macroalgae are a promising source of a vast variety of bioactive compounds with potential interest in aquaculture. In addition to their sustainable and renewable nature, numerous evidences have been reported pointing to positive effects on fish growth, nutrient utilization, and disease resistance. Nevertheless, the effects on fish quality objective parameters have been scarcely explored. In this study we assessed the influence of Ulva ohnoi included at low level (5%) in a diet for Senegalese sole (Solea senegalensis) on several quality attributes of fish (proximate analysis, texture profile analysis, lipid oxidation, fatty acid profile, pH, water holding capacity, and colour parameters). A 270-d feeding trial was carried out, in which juvenile animals were fed with an Ulva-enriched diet only for 90 d out of the total 270-d study. This enabled to evaluate whether the possible effects on fish were transitory or persistent at the end of the assay. Besides modest effects on fish growth at early stages, the differences attributable to Ulva supplementation were mostly focused on the lipid fraction, texture, and colour parameters. Thus, Ulva diet reduced muscle total lipid content and favoured muscle selective retention of n-3 polyunsaturated fatty acids (PUFA), not least eicosapentaenoic acid (EPA) and docosahexaenoic (DHA) acid, and also diminished lipid oxidation, especially after a period of frozen storage. In terms of consumers' acceptability, seaweed supplementation impacted favourably on fillet texture and colour attributes, namely by increasing lightness (L*) and yellowness (b*), whilst reducing redness (a*). These results are particularly remarkable taking into account that low inclusion level was considered (5%), and above all, that Ulva supplementation was interrupted after 90 d, but the effects mentioned persisted at least up to 270 d. These deferred long-term effects might well be of practical interest when it comes to modifying quality attributes of edible fish.

Évaluation objective de la qualité du sommeil chez les patients souffrant d’une rupture de la coiffe des rotateurs

IntroductionSleep dysfunction in patients with rotator cuff tears has been previously evaluated only using subjective measures. Objective parameters of sleep quality amongst rotator cuff tear patients are scarce in the literature. The aim of this study is to compare objective sleep data to historical controls and to subjective patient reported sleep quality in patients with rotator cuff tears. HypothesisWe hypothesized that patients with rotator cuff tears would demonstrate objectively poor sleep quality based on actigraphy when compared to a historical control group. Secondarily, we hypothesize that objective sleep quality measures will correlate poorly with traditionally used questionnaires and other subjective assessments. Materials and methodsTwenty patients with full-thickness rotator cuff tears wore a highly validated activity monitor for 2 consecutive weeks for objective assessment and completed a sleep diary during the same period. Patients completed multiple questionnaires pertaining to their shoulder function and subjective assessment of sleep quality. Objective sleep assessments were compared to patients’ sleep diary data and to subjective sleep data from a historical cohort of 969 healthy adults aged 57–97 years. ResultsMean total sleep time, sleep onset latency, wake after sleep onset (WASO), and sleep efficiency were all significantly worse in the study cohort compared to the historical cohort (p=0.0338, p=0.0040, p<0.0001, and p=0.0474, respectively). Pittsburgh Sleep Quality Index (PSQI) scores did not correlate with sleep efficiency (r=0.3143, p=0.2040) or WASO (r=−0.3068, p=0.2153). Visual analog scale scores correlated with PSQI scores (r=0.5260, p=0.0249) and Epworth Sleepiness Scale scores (r=0.4863, p=0.0407). Patients tended to overreport their time spent asleep via a sleep diary compared to objective time asleep (p=0.0050). DiscussionThis study of objective sleep measures demonstrated poor sleep quality in patients with rotator cuff tears with shorter sleep duration, frequent awakenings, and decreased efficiency. Subjective assessments of sleep did not correlate with objective findings. Level of evidenceLevel II, prospective cohort study.

QoE in video streaming over ad hoc networks: comparison and analysis of AODV and OLSR routing protocols

Video streaming services are easily among of the most solicited services on the internet. Indeed, they are single-handedly accountable for up to 85% of overall internet traffic. In this vein, new venues of marketing strategies are constantly witnessing the emergence of ever-higher quality standards emphasising on end-user appraisal. And so, in addition to the quality of service (QoS) which is built upon network-oriented metrics, it behooves us to pay greater heed to the quality of experience (QoE); whence ensuring decent overall performance re-emerges as a challenge to be reckoned with. In fact, the extant routing protocols tend to be network-oriented and are, as such, chiefly dependent upon objective quality parameters. This article purports to experiment on video transmission through an ad hoc network, based on the two emblematic routing protocols (i.e., AODV and OLSR), so as to pinpoint the one most in-step with the afore-mentioned subjective quality (QoE) trends.

Objective assessment of sleep quality in patients with rotator cuff tears

IntroductionSleep dysfunction in patients with rotator cuff tears has been previously evaluated only using subjective measures. Objective parameters of sleep quality amongst rotator cuff tear patients are scarce in the literature. The aim of this study is to compare objective sleep data to historical controls and to subjective patient-reported sleep quality in patients with rotator cuff tears. HypothesisWe hypothesized that patients with rotator cuff tears would demonstrate objectively poor sleep quality based on actigraphy when compared to a historical control group. Secondarily, we hypothesize that objective sleep quality measures will correlate poorly with traditionally used questionnaires and other subjective assessments. Materials and methodsTwenty patients with full-thickness rotator cuff tears wore a highly validated activity monitor for 2 consecutive weeks for objective assessment and completed a sleep diary during the same period. Patients completed multiple questionnaires pertaining to their shoulder function and subjective assessment of sleep quality. Objective sleep assessments were compared to patients’ sleep diary data and to subjective sleep data from a historical cohort of 969 healthy adults aged 57–97 years. ResultsMean total sleep time, sleep onset latency, wake after sleep onset (WASO), and sleep efficiency were all significantly worse in the study cohort compared to the historical cohort (p=0.0338, p=0.0040, p<0.0001, and p=0.0474, respectively). Pittsburgh Sleep Quality Index (PSQI) scores did not correlate with sleep efficiency (r=0.3143, p=0.2040) or WASO (r=−0.3068, p=0.2153). Visual analog scale scores correlated with PSQI scores (r=0.5260, p=0.0249) and Epworth Sleepiness Scale scores (r=0.4863, p=0.0407). Patients tended to overreport their time spent asleep via a sleep diary compared to objective time asleep (p=0.0050). DiscussionThis study of objective sleep measures demonstrated poor sleep quality in patients with rotator cuff tears with shorter sleep duration, frequent awakenings, and decreased efficiency. Subjective assessments of sleep did not correlate with objective findings. Level of evidenceLevel II, prospective cohort study.

Effects of alginate coating enriched with tannins on shelf life of cultured rainbow trout (Oncorhynchus mykiss) fillets

This study assesses the potential of two tannins, tannic acid (TAN) and quebracho tannin (QUE), to preserve objective quality parameters of rainbow trout fillets throughout a 15-d cold storage period, applied either alone or combined with alginate coating. Untreated fillets (C), and a set of fillets treated with ascorbic acid (ASC) were also included. All the additives reduced microbial counts and lipid oxidation of fillets, being the effects of TAN and QUE at least comparable to those of ASC, the most widely used antioxidant for fresh fish. The results also indicate that alginate by itself reduced lipid oxidation at late stages of the storage period, and increased fillet lightness (L*) as well, but caused scarce effects on other parameters involved in fillet deterioration. However, alginate and additives applied together enhanced the effects of the additives alone, especially regarding microbial and lipid oxidative parameters, this enabling prolonged shelf life of fillets. These valuable properties of commercial tannins, together with their natural origin and large-scale availability, might well enable further applicability of these substances to fish fillets preservation, not least with regard to coloured species, such as rainbow trout.

Evaluation of image quality and radiation dose in low tube voltage coronary computed tomography angiography.

BACKGROUNDCoronary computed tomography angiography (CCTA) is an important modality in diagnosis of coronary artery disease (CAD). Owing to the fact that computed tomography (CT) examinations are performed using ionizing radiation; applying radiation dose-reduction strategies seems to be necessary. Lowering tube voltage (in kV) according to the patient’s body mass index (BMI) or weight is an approach that is investigated by many researchers. The goal of this study was to evaluate the impact of low tube voltage CCTA on radiation dose and image quality in order to decrease radiation dose in selected patients who meet inclusion criteria of the introduced protocol.METHODSPatients with clinical indications of CCTA who met inclusion criteria were classified in two groups randomly. Imaging of two groups was performed using 120 kV and 100 kV, respectively. Subjective and objective parameters of image quality and radiation dose of two groups were measured. Afterward, data were analyzed by appropriate statistical tests using SPSS software.RESULTSWhile differences in image quality between two groups were not significant, radiation dose of patients who underwent 100 kV CCTA was significantly lower than the other group. Effective doses (EDs) of first and second groups were 22.30 ± 5.48 mSv and 13.82 ± 2.00 mSv, respectively (P < 0.001).CONCLUSIONLowering tube voltage in non-obese patients is an effective and practical approach to radiation dose reduction without missing image quality that should be considered especially for female patients.

Research and development of sound quality in portable testing and evaluation system based on self-adaptive neural network

Ordinary microphone cannot accurately reflect authentic human feelings in the sound quality testing and evaluation. By contrast, professional artificial head system can produce similar results with human feelings through the simulation of human auditory system, but it is expensive and unable to occupy the driver's seat to record the vehicle sound. Here we design a portable system based on self-adaptive neural network (NN) which can obtain the result of sound quality evaluation similar with the artificial head. The system consists of binaural microphone, signal conditioning units (SCU), and mobile phone. Firstly, sound is perceived by binaural microphone, processed by SCU, and collected by mobile phone. Initial sound quality objective parameters are calculated after noise reduction for sound signals and then the accurate objective parameters can be obtained from the initial parameters through the trained NN model. To train the model, the portable system and the HEAD system are simultaneously used to collect sound sample as the input and output sample sets under different conditions. After the input samples are preprocessed, wavelet entropy eigenvalues based on the best tree wavelet packet analysis are calculated along with psychoacoustic parameters of all the samples. Finally, we obtain the combined feature vectors and successfully train the model. Checked by the practical data, the relative error of sound quality objective parameters produced by the NN model is less than 5% compared with the HEAD system, which conforms to general engineering requirements. This inexpensive and user-friendly portable system paves a new way in the sound quality testing and evaluation that are highly desirable for vehicle acoustical designs and improvements.

Saliency enabled compression in JPEG framework

Under low bit-rate requirements, JPEG baseline causes compression artifacts in the image. Through this paper, a novel region-of-interest (ROI) dependent quantization method in JPEG framework is proposed. The proposed method judiciously quantizes DCT coefficients belonging to salient and non-salient regions of the image. In this work, multiple ROIs are optimally identified and ranked by using variances. The number of classes is adaptively calculated using goodness-of-segmentation. After the number of classes and their ranks are obtained, the image is divided into blocks of size . These blocks may belong to more than one class and hence these are ranked based on their membership in various classes. 2D-DCT coefficients of each block are obtained and then quantized adaptively based on their ranks. Overhead for rank information of blocks is minimized by applying delta-encoding. Results are analyzed in terms of objective quality parameters and visual perception and found that the blocking artifacts in the proposed method are significantly lower than JPEG. The efficiency of the proposed method is demonstrated by results of recently published similar methods and the former is found superior in terms of quality of the reconstructed image.

Comparison of Radiation Dose and Image Quality of Abdominopelvic CT Using Iterative (AIDR 3D) and Conventional Reconstructions

The purpose of this study is to compare radiation dose and image quality of abdominopelvic CT studies reconstructed with iterative and conventional techniques. This retrospective study enrolled 99 patients who underwent abdominopelvic CT examinations with the portal venous phase images reconstructed with both filtered back projection and Adaptive Iterative Dose Reduction 3D (AIDR 3D) at different time points. Subjective assessment of image quality was performed by two radiologists who scored axial images for overall quality, sharpness, noise, and acceptability in a blinded fashion. The SD of the mean attenuation of the liver, aorta, and paraspinal muscle (as a measurement of image noise) and contrast-to-noise and signal-to-noise ratios for liver and aorta were used as objective parameters of image quality. Radiation dose parameters included CT dose index volume (CTDIvol), dose-length product, effective dose (ED), and size-specific dose estimate (SSDE). Results were compared for different body mass index (BMI; weight in kilograms divided by the square of height in meters) categories. Paired t test and McNemar paired tests for noninferiority were used, with p < 0.05 considered statistically significant. We obtained a 62.5% mean reduction in CTDIvol, a 58% mean reduction in ED, and a 63% mean reduction in SSDE when AIDR 3D was used (p < 0.001). Subjective parameters of image quality were considered noninferior for AIDR 3D studies compared with filtered back projection (p < 0.001), except for the sharpness of images of patients with BMI 20-24.9. Variable results were found regarding objective assessment of image quality. AIDR 3D allowed a significant reduction in radiation dose of abdominopelvic CT examinations without a loss of image quality in general.

CTPA protocol optimisation audit: challenges of dose reduction with maintained image quality

To assess computed tomography (CT) pulmonary angiography (CTPA) dose and image quality in a large teaching hospital, and subsequently, to optimise the protocol in order to reduce the dose without affecting image quality. Dose-length product (DLP), patient size, and objective quality parameters (contrast-to-noise ratio and signal-to-noise ratio on standardised levels) were recorded from 31 patients undergoing CTPA, where also a subjective image quality evaluation was carried out independently by three specialist cardiothoracic consultant radiologists. An equivalent objective and subjective quality assessment was carried out on a cohort of the same size in a different tertiary healthcare centre. Moreover, experimental tests using anthropomorphic chest phantoms were performed, using different scan parameters. In light of the above analysis, two of the scanner settings for CTPA were modified, i.e., the SureExposure pre-set was changed to "Standard" noise level, quantified with standard deviation (SD) of 19, and the minimum amperage setting lowered from 80 to 40mA. A second cohort of patients using this new protocol was audited, following the same methodology. The average DLP of patients undergoing CTPA was initially found to be higher than both local and national dose reference levels (DRLs; 559 versus 300mGy·cm and 400mGy·cm, respectively). The new protocol led to a reduction in average DLP (359mGy·cm) while the image quality, assessed by three cardiothoracic consultant radiologists, was preserved. The CTPA protocol was implemented in the Royal Infirmary of Edinburgh resulting in significant dose reduction, and is now compliant with national and local DRLs. The image quality was maintained.