Beyond the base pairs: comparative genome-wide DNA methylation profiling across sequencing technologies.

Deoxyribonucleic acid (DNA) methylation plays a key role in gene regulation and is critical for development and human disease. Techniques such as whole-genome bisulfite sequencing (WGBS) and reduced representation bisulfite sequencing (RRBS) allow DNA methylation analysis at the genome scale, with Illumina NovaSeq 6000 and MGI Tech DNBSEQ-T7 being popular due to their efficiency and affordability. However, detailed comparative studies of their performance are not available. In this study, we constructed 60 WGBS and RRBS libraries for two platforms using different types of clinical samples and generated approximately 2.8 terabases of sequencing data. We systematically compared quality control metrics, genomic coverage, CpG methylation levels, intra- and interplatform correlations, and performance in detecting differentially methylated positions. Our results revealed that the DNBSEQ platform exhibited better raw read quality, although base quality recalibration indicated potential overestimation of base quality. The DNBSEQ platform also showed lower sequencing depth and less coverage uniformity in GC-rich regions than did the NovaSeq platform and tended to enrich methylated regions. Overall, both platforms demonstrated robust intra- and interplatform reproducibility for RRBS and WGBS, with NovaSeq performing better for WGBS, highlighting the importance of considering these factors when selecting a platform for bisulfite sequencing.

Reduction of ringing artifacts induced by diaphragm drifting in free-breathing dynamic pulmonary MRI using 3D koosh-ball acquisition.

PURPOSE: To reduce the ringing artifacts of the motion-resolved images in free-breathing dynamic pulmonary MRI. METHODS: A golden-step based interleaving (GSI) technique was proposed to reduce ringing artifacts induced by diaphragm drifting. The pulmonary MRI data were acquired using a superior-inferior navigated 3D radial UTE sequence in an interleaved manner during free breathing. Successive interleaves were acquired in an incoherent fashion along the polar direction. Four-dimensional images were reconstructed from the motion-resolved k-space data obtained by retrospectively binning. The reconstruction algorithms included standard nonuniform fast Fourier transform (NUFFT), Voronoi-density-compensated NUFFT, extra-dimensional UTE, and motion-state weighted motion-compensation reconstruction. The proposed interleaving technique was compared with a conventional sequential interleaving (SeqI) technique on a phantom and eight subjects. RESULTS: The quantified ringing artifacts level in the motion-resolved image is positively correlated with the quantified nonuniformity level of the corresponding k-space. The nonuniformity levels of the end-expiratory and end-inspiratory k-space binned from GSI data (0.34 ± 0.07, 0.33 ± 0.05) are significantly lower with statistical significance (p < 0.05) than that binned from SeqI data (0.44 ± 0.11, 0.42 ± 0.12). Ringing artifacts are substantially reduced in the dynamic images of eight subjects acquired using the proposed technique in comparison with that acquired using the conventional SeqI technique. CONCLUSION: Ringing artifacts in the motion-resolved images induced by diaphragm drifting can be reduced using the proposed GSI technique for free-breathing dynamic pulmonary MRI. This technique has the potential to reduce ringing artifacts in free-breathing liver and kidney MRI based on full-echo interleaved 3D radial acquisition.

Robust, Reproducible, and Scalable Synthesis of Silver Nanocubes.

It remains a challenge to accomplish colloidal synthesis of noble-metal nanocrystals marked by high quality, large quantity, and batch-to-batch consistency. Here we report a self-airtight setup for achieving robust, reproducible, and scalable production of Ag nanocubes with uniform and controlled sizes from 18 to 60 nm. Different from the conventional open-to-air setup, the self-airtight system makes it practical to stabilize the reaction condition by minimizing the loss of volatile reagents. The new setup also allows us to easily optimize the amount of O2 (from air) trapped in the system, ensuring burst nucleation of single-crystal seeds, followed by their slow growth into nanocubes. Most significantly, the new setup allows for the production of Ag nanocubes at gram quantities without sacrificing uniformity, corner/edge sharpness, controlled size, and high purity across different batches. The availability of high-quality Ag nanocubes in such a large quantity is anticipated to substantially boost their use in applications related to plasmonics, catalysis, and biomedicine.

Twist exome capture allows for lower average sequence coverage in clinical exome sequencing.

BACKGROUND: Exome and genome sequencing are the predominant techniques in the diagnosis and research of genetic disorders. Sufficient, uniform and reproducible/consistent sequence coverage is a main determinant for the sensitivity to detect single-nucleotide (SNVs) and copy number variants (CNVs). Here we compared the ability to obtain comprehensive exome coverage for recent exome capture kits and genome sequencing techniques. RESULTS: We compared three different widely used enrichment kits (Agilent SureSelect Human All Exon V5, Agilent SureSelect Human All Exon V7 and Twist Bioscience) as well as short-read and long-read WGS. We show that the Twist exome capture significantly improves complete coverage and coverage uniformity across coding regions compared to other exome capture kits. Twist performance is comparable to that of both short- and long-read whole genome sequencing. Additionally, we show that even at a reduced average coverage of 70× there is only minimal loss in sensitivity for SNV and CNV detection. CONCLUSION: We conclude that exome sequencing with Twist represents a significant improvement and could be performed at lower sequence coverage compared to other exome capture techniques.

Use of Resonant Acoustic Mixing Technology for Ultra-Low-Dose Blending in a Single-Step Mixing Process.

PURPOSE: To evaluate the use of resonant acoustic mixing (RAM) technology for homogenous blending of a morphologically challenging model API in low-dose concentrations (<0.1% w/w), and assess the potential for blend uniformity (BU) optimization. METHODS: Caffeine (CAF) mixing was carried out using a LabRAM I benchtop mixer. Uniformity was assessed under a range of mixing conditions and sample preparation procedures in order to optimize system performance. The capacity for microscale mixing was evaluated from final parameters for 0.05% and 0.0125% CAF blends. RESULTS: Upon optimization, RAM was able to accurately prepare homogeneous mixtures of <0.1% CAF in dilutions of up to 1 part per 8,000. Results from a 0.05% blend targeting 125 µg CAF dosage amounts revealed an AV score of 8.8 while a 0.0125% w/w blend accurately prepared 25 µg of CAF with 99.3% accuracy (98.7% label claim) and AV of 10.1. Microscale mixing in the 0.05% w/w blend was confirmed from plots of BU data against sample size demonstrating a slope of 0.05 within the range of 250-10 mg sample (125-5 µg CAF). L1 BU criteria only failed at the level of 2 µg CAF, despite target precision to 26 nanograms (98.7% label claim). CONCLUSIONS: This study presents the first instance of a homogenously mixed <0.1% (w/w) blend using RAM technology and demonstrate the suitability for reproducible dosing of single-digit microgram drug amounts. Uniformity is documented for API amounts 60x smaller than a recent report has shown and 10,000x smaller than achieved previously with CAF.

Facile Integration of Hanztsch's Switch-Off/On Modeled Fluorogenic Probe for Feasible Tagging and Tracking of the Midodrine Drug in Different Matrices; First Evaluation of the Method's Greenness, Whiteness, Blueness, Quantum Yield, and Tablets' Content Homogeneity.

The proposed investigation follows a certain methodology to guarantee that the procedure employed is sustainable and green. It is noteworthy to mention that various tools have been implemented as potential indicators of environmental sustainability (greenness and whiteness). From a novelty viewpoint, a new tool, BAGI, for the method's blueness evaluation was applied to the planned method and showed a high applicability score. Fortunately, the WAC concept, which combines ecological and functional variables using the Green/Red/Blue design (RBG 12 tool), identifies the established analytical approach as white. In the planned study, a new, green, simple, nano-trace-sensitive, original fluorimetric methodology was established to analyze and assess midodrine hydrochloride content in different matrices. Midodrine's primary amine moiety reacts with Diacetylmethane/Oxymethylene reagent in an acetate buffer, which leads to generating a fluorescent dihydrolutidine derivative (Hantzsch-named reaction). Consequently, the signal strength of this compound was quantified at 487 nm, with an excitation wavelength of 426 nm. This analysis indicated that the technique exhibited linearity within the range of 0.05 to 1.1 µg mL-1 concentrations, accompanied by remarkably good sensitivity values (LOD and LOQ). The methodology employed in this examination was subjected to validation following the rules recognized by ICH. From the perspective of pharmacy and chemistry, the method presented in this study was successfully employed to analyze commercially available tablets, oral drops, and human fluids. The outcomes obtained demonstrated satisfactory recovery rates without any interference from excipients. Following the USP recommendations, the intended technique was finally implemented to explore the content homogeneity evaluation.

Reconsidering the Lessons Learned from the 1970 Southern Corn Leaf Blight Epidemic.

The southern corn leaf blight epidemic of 1970 caused estimated losses of about 16% for the U.S. corn crop, equivalent to about $8 billion in current terms. The epidemic was caused by the prevalence of Texas male sterile cytoplasm (cms-T), used to produce most of the hybrid corn seed planted that year, combined with the emergence of a novel race of the fungus Cochliobolus heterostrophus that was exquisitely virulent on cms-T corn. Remarkably, the epidemic lasted just a single year. This episode has often been portrayed in the literature and textbooks over the last 50 years as a catastrophic mistake perpetrated by corn breeders and seed companies of the time who did not understand or account for the dangers of crop genetic uniformity. In this perspective article, we aim to present an alternative interpretation of these events. First, we contend that, rather than being caused by a grievous error on the part of the corn breeding and seed industry, this epidemic was a particularly unfortunate, unusual, and unlucky consequence of a technological advancement intended to improve the efficiency of corn seed production for America's farmers. Second, we tell the story of the resolution of the epidemic as an example of timely, meticulously applied research in the public sector for the public good.

Yellowness in skin complexion: Analysis of self-perception of women in China evaluated against clinical parameters of yellowness.

BACKGROUND: Skin "yellowness" is an abstract and subjective term, without a definitive measurement protocol. Objectives were to analyze Chinese women's self-perception of skin yellowness and associated parameters and identify objective clinical measurements that correlate with these perceptions. METHODS: Following focus group discussions, criteria for skin yellowness were defined, and validated by volunteer rankings of facial images. A typology study of 185 women was performed. Participants were grouped into yellow (Color Uniformity, Brightness and Transparency (CUBT) yellow scale grade > 3, chromameter b* value > 16) and non-yellow (CUBT yellow scale grade < 2, b* value < 14) groups. Participants self-evaluated their skin on yellowness, transparency, skin uniformity, dullness, radiance, oiliness, and texture. Expert assessments were performed to grade sebaceous pores, ocular area pigmentation, pigmentary spots and CUBT scores. Instrumental analysis of the skin was employed using corneometer, sebumeter, mexameter chromameter, and AGE reader. RESULTS: Women in the yellow group self-evaluated their skin as significantly duller, less uniform, and less radiant than women in the non-yellow group (P ≤ 0.05). Higher levels of ocular area pigmentation and lower facial skin uniformity and brightness (P < 0.001) were observed in women with yellow skin. CUBT expert grading showed lower pink skin color, but significantly higher beige, yellow, and olive pigmentation (P ≤ 0.05) in women in the yellow skin group. Melanin and b* values were significantly higher in women with yellow skin while L value was significantly lower. CONCLUSION: Self-perceived skin yellowness in Chinese women correlates to chromameter and mexameter measurements, as well as expert evaluation of ocular pigmentation and CUBT parameters.

Assessment of evidence based care and uniformity of practices through implementation of standardized medical protocols and guidelines in pediatric emergency departments.

OBJECTIVE: This study aims to assess compliance with medical protocols and outcomes, as well as determine the consistency in clinical practice across different Pediatric Emergency Departments (PED) in public sector hospitals of a low-middle income country. METHODS: A retrospective analysis was conducted on patients presenting to PEDs of five public sector hospitals, namely Civil Hospital Karachi (PED 1), National Institute of Child Health (PED 2), Abbasi Shaheed Hospital (PED 3), Sheikh Zayed Hospital Larkana (PED 4), and Ghulam Muhammad Mahar College Hospital Sukkur (PED 5). The analysis covered a three-month period from February 1, 2023, to April 30, 2023. Patients diagnosed with Acute asthma, Sepsis, and Septic Shock during the study duration were included. Outcomes for each disease were evaluated based on compliance with standardized protocols.The statistical significance of data was measured by adding the p values. RESULTS: 110,450 patients visited PED during the study period and mortality rate was 2% (n=2193). 12% (13,240) were diagnosed with the three diseases during the study period. Sepsis was on top (74%, n=9,751), followed by Septic Shock (14%, n=1898), and Acute Asthma (12%, n=1591). The overall compliance rate for the three diseases was 77% (n = 10,240). Adherence to standard protocols were 98% (n = 1561) for acute asthma, 85% (n = 8240) for Sepsis, and 23% (n = 439) for Septic Shock across the five emergency departments. Of the patients who were managed according to standard protocol, 31% (n = 3135) were discharged, 30% (n- 3094) were admitted, 11% (n = 1151) were referred, 15% (n = 1501) left against medical advice and 13% (n = 1359) did not survive. On the other hand, in patients where there was noncompliance to standard protocols, 27% (n = 805) did not survive, 27% (n = 807) were discharged, 24% (n = 710) were admitted, 8% (n = 260) were referred and 14% (n = 418) left against medical advice. The differences in adherence rates among the three diseases were statistically significant (p < 0.001). CONCLUSION: The overall mortality rate was 2% in these five emergency departments and the medical protocol was followed in every third patient out of fourth in those three diseases. The survival rate till ED disposition was doubled in those patients for whom medical protocols were followed as compared to those for non-compliant. The majority of PED demonstrated good compliance with standardized practices. However, this study identified areas that require attention and further training, especially early recognition and management of septic shock where compliances seem alarmingly low. Our data analysis indicates that adherence to guidelines has resulted in uniformity in clinical practice and the provision of early evidence-based quality care. Nevertheless, there is still room for improvement in ensuring consistent adherence to medical protocols in pediatric emergency settings and thus improving patient outcomes.

Achilles tendon and triceps surae muscle properties in athletes.

PURPOSE: The aim of this study was to investigate internal Achilles tendon (AT) displacement, AT shear wave velocity (SWV), and triceps surae (TS) muscle shear modulus in athletes. METHODS: Internal AT displacement was assessed using ultrasound during isometric contraction. Shear wave elastography was used to assess AT SWV (m × s-1) at rest and TS muscle shear modulus (kPa) during passive ankle dorsiflexion. RESULTS: A total of 131 athletes participated in this study. Athletes who had not exercised within two days had greater AT non-uniformity and mean anterior tendon displacement, and lower SWV at the proximal AT measurement site (mean difference [95% CI]: 1.8 mm [0.6-2.9], p = 0.003; 1.6 mm [0.2-2.9], p = 0.021; - 0.9 m × s-1 [- 1.6 to - 0.2], p = 0.014, respectively). Male basketball players had a lower mean AT displacement compared to gymnasts (- 3.7 mm [- 6.9 to - 0.5], p = 0.042), with the difference localised in the anterior half of the tendon (- 5.1 mm [- 9.0 to - 1.1], p = 0.022). Male gymnasts had a smaller absolute difference in medial gastrocnemius-minus-soleus shear modulus than basketball players (59.6 kPa [29.0-90.2], p < 0.001) and track and field athletes (52.7 kPa [19.2-86.3], p = 0.004). Intraclass correlation coefficients of measurements ranged from 0.720 to 0.937 for internal AT displacement, from 0.696 to 0.936 for AT SWE, and from 0.570 to 0.890 for TS muscles. CONCLUSION: This study provides a reliability assessment of muscle and tendon SWV. The relative differences in passive TS muscle shear modulus suggest sport-specific adaptation. Importantly, in healthy individuals, lower AT displacement after exercise may reflect the time required for tendon recovery.

Optimization of uniformity in coronary artery enhancement using a bolus tracking technique with a dual region of interest in coronary computed tomographic angiography.

BACKGROUND: Consistent coronary artery enhancement is essential to achieve accurate and reproducible quantification of coronary plaque composition. PURPOSE: To optimize coronary artery uniformity of enhancement using a bolus tracking technique with a dual region of interest (ROI) in coronary computed tomography angiography (CCTA) on a 320-detector CT scanner. MATERIAL AND METHODS: This prospective study recruited 100 consecutive patients who underwent CCTA and were randomly divided into two groups, namely, a manual trigger group (n = 50), in which a manual fast start technique was used to start the diagnostic scan with the visual evaluation of attenuation in the left atrium and left ventricle, and an automatic trigger group (n = 50), in which a bolus tracking technique was used to automatically start the breath-holding command and diagnostic scan with two ROIs placed in the right and left ventricles. Coronary artery image quality was assessed using quantitative and qualitative scores. The enhancement uniformity was characterized by attenuation variability of the ascending aorta (AAO) and coronary arteries. RESULTS: No statistically significant differences in the image quality of the coronary arteries were observed between the two groups (all P > 0.05). The coefficients of variation (COVs) of arterial attenuation in the automatic trigger group were significantly smaller than in the manual trigger group (AAO: 9.89% vs. 17.93%; LMA: 10.35% vs. 18.98%; LAD proximal: 12.09% vs. 20.84%; LCX proximal: 11.85% vs. 20.95%; RCA proximal: 12.13% vs. 20.84%; all P < 0.05). CONCLUSION: The automatic trigger technique accompanied with dual ROI provides consistent coronary artery enhancement and optimizes coronary artery enhancement uniformity in CCTA on a 320-detector CT scanner.

Determination of omeprazole via fluorescence-quenching methodology; application to content uniformity testing.

A new, proven, economical spectrofluorimetric approach has been used to determine the proton pump inhibitor omeprazole (OMP). This innovative technique is based on the ability of OMP to quench the native fluorescence of the mercurochrome dye in an acidic (pH 3.6) solution. Because it was discovered that quenching is proportional to the drug concentration, this dye was used as a sensor for OMP detection. The fluorescence intensity was measured at 518/540 nm, and its linear response ranged from 0.2-10.0 µg/mL with a linear coefficient of 0.9999. The computation yielded a limit of quantification (LOQ) of 0.20 µg/mL and a limit of detection (LOD) of 0.07 µg/mL. Every circumstance and element impacting the reaction product was examined in detail. Pharmacopeial standards carried out the validation. The approved method investigated several commercial preparations and formulations, and the results were favorably compared with those provided by a reference method. According to United States Pharmacopeia (USP) rules, content consistency for two distinct formulations was evaluated.

Optical design of low-location illumination based on asymmetric double freeform surfaces.

The development of optical optics for low-location road lighting is a challenging problem in providing high luminance and uniformity of illumination and meeting many other specific requirements. This study proposes an optical design method of low-location illumination based on an asymmetric double freeform surface lens. The ray emitted from the light source is refracted and reflected through the different surface types to the corresponding area of the receiving surface. In the design example, the road has dual-side mounted luminaires and a width of 6 m, and a height of 0.8 m. Simulation results indicate that, compared with conventional high-pole streetlights, the luminance uniformity had increased from 0.60 to 0.66, the illuminance uniformity had improved from 0.75 to 0.86, and the glare had been reduced.

Isoquinoline-based intrinsic fluorescence assessment of erythropoiesis-stimulating agent, Roxadustat (FG-4592), in tablets: applications to content uniformity and human plasma evaluation.

In the present study, a first validated and green spectrofluorimetric approach for its assessment and evaluation in different matrices was investigated. After using an excitation wavelength of 345 nm, Roxadustat (ROX) demonstrates a highly native fluorescence at an emission of 410 nm. The influences of experimental factors such as pH, diluting solvents, and different organized media were tested, and the most appropriate solvent choice was ethanol. It was confirmed that there was a linear relationship between the concentration of ROX and the relative fluorescence intensity in the range 60.0-1000.0 ng ml-1, with the limit of detection and limit of quantitation, respectively, being 17.0 and 53.0 ng ml-1. The mean recoveries % [±standard deviation (SD), n = 5] for pharmaceutical preparations were 100.11% ± 2.24%, whereas for plasma samples, they were 100.08 ± 1.08% (±SD, n = 5). The results obtained after the application of four greenness criteria, Analytical Eco-Scale metric, NEMI, GAPI, and AGREE metric, confirmed its eco-friendliness. In addition, the whiteness meter (RGB12) confirmed its level of sustainability. The International Council for Harmonisation (ICH) criteria were used to verify the developed method through the study in both spiked plasma samples and content uniformity evaluation. An appropriate standard for various applications in industry and quality control laboratories was developed.

Exploitation of erythrosine B as a fluorometric marker for lurasidone determination through electrostatic attraction; application to content uniformity test.

A recently developed antipsychotic drug, lurasidone, was determined using a simple, sensitive, and eco-friendly spectrofluorimetric approach. The suggested approach was based on the quantifiable quenching impact of lurasidone on the inherent fluorescence of erythrosine B in an acidic environment employing a Teorell-Stenhagen buffer (pH 4). Following excitation at 530 nm, the quenching of erythrosine B fluorescence was monitored at 552 nm. The system variables were systematically optimized to enhance the formation of the lurasidone-erythrosine B ion pair for analytical purposes. A linear calibration graph was built in the range of 20-600 ng mL-1 with 0.9998 as a coefficient of correlation. The quantitation and detection limits were 13.5 and 4.5 ng/mL, respectively. The analytical validity of the designed approach was assessed with respect to International Council on Harmonization (ICH) guiding principles. The proposed methodology was employed with high recoveries for assessing lurasidone in bulk powder and its therapeutic tablet dosage form. Additionally, the uniformity of tablet formulations was tested using the developed approach. Finally, the established approach was assessed for its greenness using various tools.

Efficient application of Pyrosin B for nano-gram level assay of antiparkinsonian medication, rasagiline: Evaluation of tablets and content uniformity.

Rasagiline (RAS) is a medication for Parkinson's disease that increases dopamine levels in the brain by inhibiting monoamine oxidase, helping to alleviate symptoms. The proposed study aims to develop an efficient, feasible, and sensitive method for RAS assay, utilizing Pyrosin B dye, a convenient fluorescent ligand. Combining the RAS analyte with Pyrosin B ligand in a mildly acidic buffered solution rapidly quenches the native fluorescence of the ligand. This quenching results from the formation of a specific ion-dipole association complex between the lone pair-bearing atoms of the ligand and the protonated amine moiety of RAS, highlighting their interactive chemistry under these conditions. The degree of this interaction demonstrated superior sensitivity compared with reported alternatives, exhibiting a linear range of 50.0 to 1000.0 ng/mL. The method is characterized by a limit of detection (LOD) of 16.0 ng/mL and a limit of quantification (LOQ) of 48.0 ng/mL. By optimizing the RAS-Pyrosin B system, the variable parameters were finely tuned, ensuring the assay method's reliability. The method's accuracy, precision, selectivity, and robustness were validated according to International Council for Harmonization (ICH) guidelines, enabling precise and efficient analysis of RAS in the nanogram range. This method streamlines the analysis procedure and reduces environmental impact, making it a promising approach for the quality control of ParkintreatR tablets (1 mg) and other analytical applications.

Prominently selective fluorescence approach with distinctive biopharmaceutical utility for analysis of lurasidone in human plasma and urine: Application to in vitro dissolution and content uniformity testing.

A relevant approach based on the attractive inherited merits of fluorescence spectroscopy has been established for quantitative estimation of a newly approved second-generation atypical antipsychotic lurasidone (LUR) in its raw materials and pharmaceutical dosage forms. This study brings to light the strong native fluorescence of LUR at 400 nm in water after excitation at 316 nm. Different experimental parameters that may compromise the fluorescence of the drug were carefully investigated and optimized. A linear response was established between the relative fluorescence intensity and concentration over the concentration range of 50-650 ng/mL with excellent correlation (r = 0.9998). The validity of the method was evidenced in accordance with International Council for Harmonization guidelines, with minimal detection and quantification limits of 2.88 and 8.73 ng/mL, respectively. The method was effectively applied for the estimation of LUR in spiked human plasma and urine samples with acceptable recoveries. The biopharmaceutical significance of the method was heightened by its successful applications for both content uniformity and in vitro dissolution testing. Three different tools accredited the greenness character of the presented study. Eco-friendliness, effortlessness, and cost effectiveness are crucial hallmarks of our study. The presented study demonstrates potential applicability in quality control laboratories with limited resources.

Receive coil quality assurance procedure and automated analysis for ViewRay MRIdian MR-Linac.

PURPOSE: Regular receiving coil quality assurance (QA) is required to ensure image quality of an MRIdian Linac system. The manufacturer provides a spherical phantom and positioning tube for single-slice signal-to-noise ratio (SNR) and uniformity assessments. We aimed to improve imaging setup and coverage and eliminate inter-scan variability by employing multi-slice imaging of a stable phantom. Additionally, we strived to expedite analysis by developing objective, automated analysis software. METHODS: A 5300 mL cylindrical plastic bottle placed in plastic bins was scanned at isocenter using a spin-echo sequence with NEMA-recommended parameters and 18 axial slices, avoiding phantom repositioning. Acquisition was repeated with and without prescan normalization filtering and by saving uncombined element images. Obtained data were analyzed using custom open-source MATLAB code. Signal and noise images were automatically assigned, and ROIs for SNR and uniformity calculations were defined using image thresholding. SNR and uniformity pass/fail decisions were made using baseline comparisons. RESULTS: The proposed method was successfully implemented as monthly coil QA for 3.5 years. Setup and scanning took 41 min on average for a coil set. Automated image analysis was completed in a few minutes. Signal intensity peaked around +90 or -90 mm for Torso or Head/Neck coil unfiltered images. Noise peaked and minimized SNR inside ±30 mm from isocenter, while maximizing it around ±130 mm. Prescan normalization smoothed signal response, reduced SNR and increased uniformity. Individual coil element image analysis identified their position, signal or noise response and SNR. SNR and uniformity pass/fail thresholds were set for already tested and new coils. Conspicuous and subtle Torso coil malfunctions were detected considering baseline deviations of combined and individual element results. CONCLUSIONS: Our QA method eliminated observer bias and provided insights into coil function, image filtering performance and coil element location. It provided SNR and uniformity thresholds and identified faulty coil elements.

Exploring Weak Magnetic Signal Characteristics of Pipeline Welds: Insights into Stress Non-Uniformity Effects.

Weak magnetic detection technology can detect stress concentration areas in ferromagnetic materials. However, the stress non-uniform characteristics of pipeline welds lead to significant differences in stress distribution range and values between inner wall welds and outer wall welds. This discrepancy makes it crucial to further evaluate the impact of stress non-uniformity on magnetic signals. To study the magnetic signal characteristics under the influence of residual stress in weld seams, a magneto-mechanical analytical model was established based on the magnetic charge theory and the distribution characteristics of residual stress in the weld seam. The magneto-mechanical relationship and magnetic signal distribution characteristics at the inner and outer wall welds of the pipeline are calculated. Furthermore, the effects of different excitation intensities on the amplitude growth characteristics of magnetic signals are analyzed and compared. To verify the analysis model, weld detection experiments with different excitation intensities were designed. The results show that both the peak-to-valley values of the normal component and the peak values of the tangential component of the outer wall weld are lower than those of the inner wall weld. Conversely, the peak-to-valley width of the normal component and the peak width of the tangential component are greater than those of the inner wall weld. Additionally, the rate of increase in weak magnetic signal amplitude decreases in a first-order exponential relationship with increasing excitation intensity. The average decay rates of the normal and tangential component amplitude growth rates for the inner wall weld are 34.03% and 27.9%, respectively, while for the outer wall weld, they are 31.75% and 28.01%, respectively. This study contributes to the identification and quantitative assessment of weak magnetic signals in inner and outer wall welds.

MEMS Resonant Beam with Outstanding Uniformity of Sensitivity and Temperature Distribution for Accurate Gas Sensing and On-Chip TGA.

Micromechanical resonators have aroused growing interest as biological and chemical sensors, and microcantilever beams are the main research focus. Recently, a resonant microcantilever with an integrated heater has been applied in on-chip thermogravimetric analysis (TGA). However, there is a strong relationship between the mass sensitivity of a resonant microcantilever and the location of adsorbed masses. Different sampling positions will cause sensitivity differences, which will result in an inaccurate calculation of mass change. Herein, an integrated H-shaped resonant beam with uniform mass sensitivity and temperature distribution is proposed and developed to improve the accuracy of bio/chemical sensing and TGA applications. Experiments verified that the presented resonant beam possesses much better uniformity of sensitivity and temperature distribution compared with resonant microcantilevers. Gas-sensing and TGA experiments utilizing the integrated resonant beam were also carried out and exhibited good measurement accuracy.