Three-dimensional particle streak velocimetry based on optical coherence tomography for assessing preimplantation embryo movement in mouse oviduct in vivo.

The mammalian oviduct (or fallopian tube) is a tubular organ hosting reproductive events leading to pregnancy. Dynamic 3D imaging of the mouse oviduct with optical coherence tomography (OCT) has recently emerged as a promising approach to study the hidden processes vital to elucidate the role of oviduct in mammalian reproduction and reproductive disorders. In particular, with an intravital window, in vivo OCT imaging is a powerful solution to studying how the oviduct transports preimplantation embryos towards the uterus for pregnancy, a long-standing question that is critical for uncovering the functional cause of tubal ectopic pregnancy. However, simultaneously tracking embryo movement and acquiring large-field-of-view images of oviduct activity in 3D has been challenging due to the generally limited volumetric imaging rate of OCT. A lack of OCT-based 3D velocimetry method for large, sparse particles acts as a technical hurdle for analyzing the mechanistic process of the embryo transport. Here, we report a new particle streak velocimetry method to address this hurdle. The method relies on the 3D streak of a moving particle formed during the acquisition of a single OCT volume, where double B-scans are acquired at each B-scan location to resolve ambiguity in assessing the movement of particle. We validated this method with the gold-standard, direct volumetric particle tracking in a flow phantom, and we demonstrated its in vivo applications for simultaneous velocimetry of embryos and imaging of oviduct. This work sets the stage for quantitative understanding of the oviduct transport function in vivo, and the method fills in a gap in OCT-based velocimetry, providing the potential to enable new applications in 3D flow imaging.

Preparation and characterization of carvacrol/ε-polylysine loaded antimicrobial nanobilayer emulsion and its application in mango preservation.

Carvacrol is well-known natural antimicrobial compounds. However, its usage in fruit preservation is restricted owing to poor water solubility. Our study aims to address this limitation by combining carvacrol with whey protein isolate (WPI) to form nanoemulsion and enhancing antimicrobial properties and stability of nanoemulsion through ε-polylysine addition, thereby improving their application in fruit preservation. The results indicated that the nanoemulsion exhibited a double-layer structure. The physicochemical properties and storage stability were found to be favorable under the conditions of WPI (0.3 wt% v/v), Carvacrol (0.5 % v/v), and ε-polylysine (0.3 wt% v/v). In addition, the nanoemulsion had inhibitory effects on Staphylococcus aureus, Escherichia coli, and Aspergillus niger at concentrations of minimal inhibition concentration (32, 32, and 200 µg/mL, respectively). In addition, during a 7-day storage period, the nanoemulsion effectively preserved mangoes. Therefore, nanoemulsion could serve as a candidate for control of postharvest mangoes spoilage and extend its period of storage.

The synbiotic combination of probiotics and inulin improves NAFLD though modulating gut microbiota.

Prebiotics can promote the growth of probiotics, cocombine of these is called synbiotics, and synbiotics is powerful regulators of gut microbiota. Intestinal microbiota plays an important role in nonalcoholic fatty liver disease (NAFLD), so synbiotics could be a therapeutic alternative. This study aims to investigate the effect of synbiotics combination of probiotics (Streptococcus Bifidobacterium and Streptococcus thermophilus) and prebiotics (Inulin) in vivo model of early NAFLD using yogurt as carrier. The results demonstrate that the yogurt with synbiotics combination group (HS) improves the biochemical indicators related to total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and insulin resistance (IR) in mice (P< .01). HS improves the development of lipid metabolism and inflammation by activating the AMPK and NFκB signaling pathway. In addition, HS restores the intestinal barrier dysfunction and inflammation caused by a high-fat diet. The 16S rRNA demonstrates that the gut microbiota composition of mice treated with HS is significantly altered specifically, the Firmicutes/Bacteroidetes ratio is significantly lower than in HFD-fed mice (P< .01). Our findings suggest the applicability of HS in preventing obesity-related NAFLD via its antioxidant, anti-inflammatory, and improved lipid metabolism by the gut-liver axis and provide a solid theoretical foundation for developing prebiotics for the prevention of NAFLD.

Glycine Enhances Oxidative Stress Tolerance and Biocontrol Efficacy of Sporidiobolus pararoseus against Aspergillus niger Decay of Apples.

Apples are deeply loved by people because of their rich nutritional value, but they are susceptible to rotting. The use of antagonistic yeast is a promising method for controlling postharvest fruit diseases, but biocontrol efficacy of yeast will be weakened in environmental stress. In this study, the effects of glycine (Gly) on the oxidative stress tolerance and the biocontrol efficacy of Sporidiobolus pararoseus (S. pararoseus) against Aspergillus niger (A. niger) are discussed. Under the stimulation of H2O2, the yeast cells treated with Gly (1 mM) showed lower ROS content, less mitochondrial impairment and cellular oxidative damage, and the cell survival rate was significantly higher than Gly-untreated yeast. The yeast cells exposed to Gly significantly increased the activities of antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and the content of glutathione (GSH). Notably, Gly-treated yeast cells had better biocontrol efficacy against A. niger in postharvest apples. The lesion diameter and decay incidence were reduced by 17.67 mm and 79.63% compared to the control, respectively, when S. pararoseus was treated with 1 mM Gly. Moreover, Gly-treated yeast increased the antioxidant enzymes activities and their gene expression were up-regulated in apples. These results indicated that 1 mM Gly not only reduced the oxidative damage of yeast, but also induced resistance-related enzymes of apples under oxidative stress, which contributed to enhancing the biocontrol efficacy of S. pararoseus against A. niger in apples.

Discovery of isatin-ß-methyldithiocarbazate derivatives as New Delhi metallo- ß-lactamase-1 (NDM-1) inhibitors against NDM-1 producing clinical isolates.

New Delhi metallo-ß-lactamase-1 (NDM-1) poses a threat to public health due to its capability to hydrolyze nearly all ß-lactam antibiotics, leaving limited treatment options for NDM-1 positive pathogens. Regrettably, there are presently no effective NDM-1 inhibitors in clinical use. This compels us to seek new compounds to combat multi-drug resistant bacterial infections (MDR). In our study, Zndm19 was identified as a new NDM-1 inhibitor through virtual screening and an NDM-1 enzyme activity inhibition assay. Subsequently, we employed the checkerboard method, time-killing assay, and combined disk test to investigate the synergistic bactericidal efficacy of Zndm19 in combination with meropenem (MEM). Meanwhile, molecular docking and site-directed mutagenesis were conducted to uncover the crucial amino acid residues engaged in Zndm19 binding. Finally, we established a mice peritonitis infection model to assess the synergistic effect of Zndm19 and MEM in vivo. Our findings demonstrated that 16 µg/mL of Zndm19 inhibited NDM-1 activity without affecting NDM-1 expression, restoring the bactericidal activity of MEM against NDM-1-positive Escherichia coli in vitro. Furthermore, MET-67, ASP-124, HIS-189, and HIS-250 amino acid residues constituted the active site of Zndm19 in NDM-1. Importantly, this combination therapy exhibited synergistic anti-infection activity in the mice peritonitis infection model, leading to an approximate 60% increase in survival rates and reduction of tissue bacterial load, effectively combating bacterial infection in vivo. In summary, our research validates that the synthetic novel NDM-1 inhibitor Zndm19 holds promise as a drug to treat drug-resistant bacterial infections, especially those harboring NDM-1.

Wearable Photoelectric Fingertip Force Sensing System Based on Blood Volume Changes without Sensory Interference.

Monitoring the force of fingertip manipulation without disturbing the natural sense of touch is crucial for digitizing the skills of experienced craftsmen. However, conventional force sensors need to be put between the skin and the objects, which affects the natural sense of the skin. Here, we proposed a fingertip force sensing method based on changes of blood volume and designed a wearable photoelectric fingertip force sensing system (PFFS) for digitalization of traditional Chinese medicine (TCM) pulse diagnosis. The PFFS does not interfere with the fingertips' tactile sense while detecting fingertip force. This PFFS detects the change of blood volume in fingertip by photoelectric plethysmography and can obtain the change of output current under different fingertip forces. We also studied the effect of various factors on PFFS output signals, including emission lights of different wavelengths, ambient temperature, and the user's heartbeat artifact. We further established the relationship between the change of blood volume and fingertip force by combining experimental and theoretical methods. Moreover, we demonstrated the feasibility of the PFFS to detect fingertip forces under commonly used conditions in TCM pulse diagnosis without sensory interference. This PFFS also shows promise for perceiving the viscosity of objects and recognizing gestures in human-computer interaction. This work paves the way for the digitalization of fingertip forces during TCM pulse diagnosis and other fingertip forces under natural conditions.

Alnustone inhibits Streptococcus pneumoniae virulence by targeting pneumolysin and sortase A.

Streptococcus pneumoniae (S. pneumoniae) is a major Gram-positive opportunistic pathogen that causes pneumonia, bacteremia, and other fatal infections. This bacterium is responsible for more deaths than any other single pathogen in the world. Inexplicably, these symptoms persist despite the administration of effective antibiotics. Targeting pneumolysin (PLY) and sortase A (SrtA), the major virulence factors of S. pneumoniae, this study uncovered a novel resistance mechanism to S. pneumoniae infection. Using protein phenotype assays, we determined that the small molecule inhibitor alnustone is a potent drug that inhibits both PLY and SrtA. As essential virulence factors of S. pneumoniae, PLY and SrtA play a significant role in the occurrence of infection. Furthermore, evaluation using PLY-mediated hemolysis assay demonstrated alunstone had the potential to interrupt the haemolytic activity of PLY with treatment alunstone (4 µg/ml). Co-incubation of S. pneumoniae D39 SrtA with small-molecule inhibitors decreases cell wall-bound Nan A (pneumococcal-anchored surface protein SrtA), inhibits biofilm formation, and reduces biomass significantly. The protective effect of invasive pneumococcal disease (IPD) on murine S. pneumoniae was demonstrated further. Our study proposes a comprehensive bacteriostatic mechanism for S. pneumoniae and highlights the significant translational potential of targeting both PLY and SrtA to prevent pneumococcal infections. Our findings indicate that the antibacterial strategy of directly targeting PLY and SrtA with alnustone is a promising treatment option for S. pneumoniae and that alnustone is a potent inhibitor of PLY and SrtA.

Kaempferol-Driven Inhibition of Listeriolysin O Pore Formation and Inflammation Suppresses Listeria monocytogenes Infection.

Listeria monocytogenes remains a nonnegligible cause of foodborne infection, posing a critical threat to public health. Under the global antibiotic crisis, novel alternative approaches are urgently needed. The indispensable role of listeriolysin O (LLO) in the intracellular life cycle, barrier penetration, colonization, and systemic dissemination of L. monocytogenes renders it a potent drug target, which means curbing L. monocytogenes via interfering with LLO-associated pathogenic mechanisms. Here, we identified kaempferol, a natural small molecule compound, as an effective LLO inhibitor that engaged the residues Glu437, Ile468, and Tyr469 of LLO, thereby suppressing LLO-mediated membrane perforation and barrier disruption. Moreover, we found that kaempferol also suppressed host-derived inflammation in a distinct way independent of LLO inhibition. The in vivo study revealed that kaempferol treatment significantly reduced bacterial burden and cytokine burst in target organs, thereby effectively protecting mice from systemic L. monocytogenes infection. Our findings present kaempferol as a potential therapeutic application for L. monocytogenes infection, which is less likely to induce drug resistance than antibiotics because of its superiority of interfering with the pathogenesis process rather than exerting pressure on bacterial viability. IMPORTANCE Currently, we are facing a global crisis of antibiotic resistance, and novel alternative approaches are urgently needed to curb L. monocytogenes infection. Our study demonstrated that kaempferol alleviated L. monocytogenes infection via suppressing LLO pore formation and inflammation response, which might represent a novel antimicrobial-independent strategy to curb listeriosis.

Pogostone Enhances the Antibacterial Activity of Colistin against MCR-1-Positive Bacteria by Inhibiting the Biological Function of MCR-1.

The emergence of the plasmid-mediated colistin resistance gene mcr-1 has resulted in the loss of available treatments for certain severe infections. Here we identified a potential inhibitor of MCR-1 for the treatment of infections caused by MCR-1-positive drug-resistant bacteria, especially MCR-1-positive carbapenem-resistant Enterobacteriaceae (CRE). A checkerboard minimum inhibitory concentration (MIC) test, a killing curve test, a growth curve test, bacterial live/dead assays, scanning electron microscope (SEM) analysis, cytotoxicity tests, molecular dynamics simulation analysis, and animal studies were used to confirm the in vivo/in vitro synergistic effects of pogostone and colistin. The results showed that pogostone could restore the bactericidal activity of colistin against all tested MCR-1-positive bacterial strains or MCR-1 mutant−positive bacterial strains (FIC < 0.5). Pogostone does not inhibit the expression of MCR-1. Rather, it inhibits the binding of MCR-1 to substrates by binding to amino acids in the active region of MCR-1, thus inhibiting the biological activity of MCR-1 and its mutants (such as MCR-3). An in vivo mouse systemic infection model, pogostone in combination with colistin resulted in 80.0% (the survival rates after monotherapy with colistin or pogostone alone were 33.3% and 40.0%) survival at 72 h after infection of MCR-1-positve Escherichia coli (E. coli) ZJ487 (blaNDM-1-carrying), and pogostone in combination with colistin led to one or more order of magnitude decreases in the bacterial burdens in the liver, spleen and kidney compared with pogostone or colistin alone. Our results confirm that pogostone is a potential inhibitor of MCR-1 for use in combination with polymyxin for the treatment of severe infections caused by MCR-1-positive Enterobacteriaceae.

Catalytic Deoxygenation of Xylitol to Renewable Chemicals: Advances on Catalyst Design and Mechanistic Studies.

Xylitol is commonly known as one of the top platform intermediates for biomass conversion. Catalytic deoxygenation of xylitol provides an atomic and energetic efficient way to produce a variety of renewable chemicals including ethylene glycol, 1,2-propanediol, lactic acid and 1,4-anhydroxylitol. Despite a few initial attempts in converting xylitol into those products, improving catalyst selectivity towards C-O and C-C cleavage reactions remains a grand challenge in this area. To our best knowledge, there is lack of comprehensive review to summarize the most recent advances on catalyst design and mechanisms in deoxygenation of xylitol, offering important perspective into future development of xylitol transformation technologies. Therefore, in this mini-review, we have critically discussed the conversion routes involved in xylitol deoxygenation over solid catalyst materials, the nanostructures of supported metal catalysts for C-H, C-C and C-O bond cleavage reactions, and mechanistic investigation for xylitol conversion. The outcome of this work provides new insights into rational design of effective deoxygenation catalyst materials for upgrading of xylitol and future process development in converting hemicellulosic biomass.

Dryocrassin ABBA ameliorates Streptococcus pneumoniae-induced infection in vitro through inhibiting Streptococcus pneumoniae growth and neutralizing pneumolysin activity.

To explore the role of dryocrassin ABBA (ABBA) in the prevention and treatment of Streptococcus pneumoniae (S. pneumoniae) infections in vitro, a minimal inhibitory concentration test, growth curve assay, hemolysis assay, BacLight LIVE/DEAD staining experiments, oligomerization inhibition assay, time-killing test, LDH release detection assay and cytotoxicity test were performed to evaluate the efficacy of ABBA against S. pneumoniae infections in vitro. The results indicated that ABBA treatment exists bactericidal effect on S. pneumoniae at a concentration of less than 8 µg/ml. Furthermore, ABBA was effective at inhibiting the oligomerization of pneumolysin (PLY) from reducing its hemolytic activity. Meanwhile, ABBA could ameliorate cell injury by neutralizing the biological activity of PLY without cytotoxicity. In summary, ABBA was a leading compound against S. pneumoniae infections through bactericidal effect and neutralizing PLY activity.

Inhibitory Effect of Piceatannol on Streptococcus suis Infection Both in vitro and in vivo.

Suilysin (SLY) plays a critical role in Streptococcus suis infections making it an ideal target to the combat infection caused by this pathogen. In the present study, we found that piceatannol (PN), a natural compound, inhibits pore-formation by blocking the oligomerization of SLY without affecting the growth of S. suis and the expression of SLY. Furthermore, PN alleviated the J774 cell damage and the expression of the inflammatory cytokine tumor necrosis factor-α (TNF-α) and interleukin-1α (IL-1ß) induced by S. suis in vitro. The computational biology and biochemistry results indicated that PN binds to the joint region of D2 and D4 in SLY, and Asn57, Pro58, Pro59, Glu76, Ile379, Glu380, and Glu418 were critical residues involved in the binding. The binding effect between PN and SLY hindered the SLY monomers from forming the oligomers, thereby weakening the hemolytic activity of SLY. This mechanism was also verified by hemolysis analysis and analysis of KA formation after site-specific mutagenesis. Furthermore, PN protected mice from S. suis infections by reducing bacterial colony formation and the inflammatory response in target organs in vivo. These results indicate that PN is a feasible drug candidate to combat S. suis infections.

ESTIMATING RADIATION DOSE TO MAJOR ORGANS IN DENTAL X-RAY EXAMINATIONS: A PHANTOM STUDY.

The radiation doses absorbed by major organs of males and females were studied from three types of dental X-ray devices. The absorbed doses from cone-beam computed tomography (CBCT), panoramic and intraoral X-ray machines were in the range of 0.23-1314.85 µGy, and were observed to be high in organs and tissues located in or adjacent to the irradiated area, there were discrepancies in organ doses between male and female. Thyroid, salivary gland, eye lens and brain were the organs that received higher absorbed doses. The organ absorbed doses were considerably lower than the diagnostic reference level for dental radiography in China. The calculated effective radiation doses for males and females were 56.63, 8.15, 2.56 µSv and 55.18, 8.99, 2.39 µSv, respectively, when using CBCT, the panoramic X-ray machine and intraoral X-ray machine. The effective radiation dose caused by CBCT was much higher than those of panoramic and intraoral X-ray machines.

Recent Advances on Purification of Lactic Acid.

With increasing interest in developing biodegradable polymers to replace fossil-based products globally, lactic acid (LA) has been paid extensive attention due to the high environment-compatibility of its downstream products. The mainstream efforts have been put in developing energy-efficient conversion technologies through biological and chemical routes to synthesize LA. However, to our best knowledge, there is a lack of sufficient attention in developing effective separation technologies with high atom economics for purifying LA and derivatives. In this review, the most recent advances in purifying LA using precipitation, reactive extraction, emulsion liquid membrane, reactive distillation, molecular distillation, and membrane techniques will be discussed critically with respect to the fundamentals, flow scheme, energy efficiency, and equipment. The outcome of this article is to offer insights into implementing more atomic and energy-efficient technologies for upgrading LA.

Physicochemical, texture properties, and microstructure of yogurt using polymerized whey protein directly prepared from cheese whey as a thickening agent.

The aim of this study was to investigate suitability of polymerized whey protein prepared directly from cheese whey on the physicochemical, texture properties, and microstructure of the yogurt. The results indicated that addition of polymerized whey protein obtained by heating the liquid whey protein concentrate at 75°C for 10 min had no significant differences in pH, titratable acidity, total solids, protein content, viscosity, texture, and syneresis between the yogurt with polymerized liquid whey protein (YWPS) and the yogurt with polymerized whey protein concentrate. However, the YWPS had significant differences in viscosity, texture, and syneresis compared with the control yogurt. Scanning electron micrographs of YWPS displayed a compact and homogeneous protein network for polymerized whey protein solution (PWPS) samples. The 4 yogurt samples were evaluated by the quantitative descriptive analysis method, and 14 sensory attributes were analyzed by principal component analysis. All 3 principal components had significant effects on the sensory profiles, accounting for 52.3, 24.32, and 10.8% of the variability in the results, respectively. Polymerized whey protein prepared directly from cheese whey may be a good protein base as a thickening agent for yogurt making.

Physicochemical Properties and Cellular Uptake of Astaxanthin-Loaded Emulsions.

Astaxanthin, a natural pigment carotenoid, is well known for its potential benefits to human health. However, its applications in the food industry are limited, due to its poor water-solubility and chemical instability. Six different emulsifiers were used to prepare astaxanthin-loaded emulsions, including whey protein isolate (WPI), polymerized whey protein (PWP), WPI-lecithin, PWP-lecithin, lecithin, and Tween20. The droplet size, zeta potential, storage stability, cytotoxicity, and astaxanthin uptake by Caco-2 cells were all investigated. The results showed that the droplet size of the emulsions ranged from 194 to 287 nm, depending on the type of emulsifier used. The entrapment efficiency of astaxanthin was as high as 90%. The astaxanthin-loaded emulsions showed good physicochemical stability during storage at 4 °C. The emulsifier type had a significant impact on the degradation rate of astaxanthin (p < 0.05). Cellular uptake of astaxanthin encapsulated into the emulsions was significantly higher than free astaxanthin (p < 0.05). Emulsion stabilized with WPI had the highest cellular uptake of astaxanthin (10.0 ± 0.2%), followed, in order, by that with PWP (8.49 ± 0.1%), WPI-lecithin (5.97 ± 0.1%), PWP-lecithin (5.05 ± 0.1%), lecithin (3.37 ± 0.2%), and Tween 20 (2.1 ± 0.1%). Results indicate that the whey protein-based emulsion has a high potential for improving the cellular uptake of astaxanthin.

Nanostructured Metal Catalysts for Selective Hydrogenation and Oxidation of Cellulosic Biomass to Chemicals.

Conversion of biomass to chemicals provides essential products to human society from renewable resources. In this context, achieving atom-economical and energy-efficient conversion with high selectivity towards target products remains a key challenge. Recent developments in nanostructured catalysts address this challenge reporting remarkable performances in shape and morphology dependent catalysis by metals on nano scale in energy and environmental applications. In this review, most recent advances in synthesis of heterogeneous nanomaterials, surface characterization and catalytic performances for hydrogenation and oxidation for biorenewables with plausible mechanism have been discussed. The perspectives obtained from this review paper will provide insights into rational design of active, selective and stable catalytic materials for sustainable production of value-added chemicals from biomass resources.

Catalytic Transfer Hydrogenation of Biomass-Derived Substrates to Value-Added Chemicals on Dual-Function Catalysts: Opportunities and Challenges.

Aqueous-phase hydrodeoxygenation (APH) of bioderived feedstocks into useful chemical building blocks is one the most important processes for biomass conversion. However, several technological challenges, such as elevated reaction temperature (220-280 °C), high H2 pressure (4-10 MPa), uncontrollable side reactions, and intensive capital investment, have resulted in a bottleneck for the further development of existing APH processes. Catalytic transfer hydrogenation (CTH) under much milder conditions with non-fossil-based H2 has attracted extensive interest as a result of several advantageous features, including high atom efficiency (≈100 %), low energy intensity, and green H2 obtained from renewable sources. Typically, CTH can be categorized as internal H2 transfer (sacrificing small amounts of feedstocks for H2 generation) and external H2 transfer from H2 donors (e.g., alcohols, formic acid). Although the last decade has witnessed a few successful applications of conventional APH technologies, CTH is still relatively new for biomass conversion. Very limited attempts have been made in both academia and industry. Understanding the fundamentals for precise control of catalyst structures is key for tunable dual functionality to combine simultaneous H2 generation and hydrogenation. Therefore, this Review focuses on the rational design of dual-functionalized catalysts for synchronous H2 generation and hydrogenation of bio-feedstocks into value-added chemicals through CTH technologies. Most recent studies, published from 2015 to 2018, on the transformation of selected model compounds, including glycerol, xylitol, sorbitol, levulinic acid, hydroxymethylfurfural, furfural, cresol, phenol, and guaiacol, are critically reviewed herein. The relationship between the nanostructures of heterogeneous catalysts and the catalytic activity and selectivity for C-O, C-H, C-C, and O-H bond cleavage are discussed to provide insights into future designs for the atom-economical conversion of biomass into fuels and chemicals.

Comparison of image quality and radiation exposure between conventional imaging and gemstone spectral imaging in abdominal CT examination.

OBJECTIVE: To compare patients' image quality and radiation exposure between gemstone spectral imaging (GSI) with rapid kV switching technique and conventional polychromatic imaging (CPI) performed in abdominal CT examinations. METHODS: Adult patients who were referred to abdominal CT from October 2015 to March 2016 were enrolled. Unenhanced CT with CPI mode and tri-phase (arterial/portal/delayed phase) contrast-enhanced scan with GSI mode were performed with different protocols respectively. Regions of interest (ROIs) were drawn on muscle and fat. Parametric results of the image noise, signal-to-noise ratio (SNR) and clinical image quality in these regions between the monochromatic images reconstructed at 65 keV and conventional polychromatic images were compared. Radiation dose was also compared between CPI and GSI. RESULTS: 43 patients were recruited. Compared to conventional imaging, the noise level was generally not significantly different between GSI images in arterial phase and portal phase, and significantly higher (around 10%) in delayed phase. The SNR of GSI in portal phase was significantly higher than that of conventional imaging, and was similar between arterial phase/delayed phase and conventional imaging. The clinical image quality between conventional imaging and GSI was generally not significantly different. The dose length product was reduced by 0.3-20.1% in GSI compared to conventional imaging. CONCLUSION: GSI reduces the radiation exposure slightly, however maintains or even improves image quality. These results may warrant the application of GSI in patients referred for abdominal CT. Advances in knowledge: Compared to CPI, GSI reduces the radiation exposure slightly, however maintains or even improves image quality in abdominal CT. These findings may warrant the application of GSI in patients referred for abdominal CT.

Head and Neck Cancer Tumor Segmentation Using Support Vector Machine in Dynamic Contrast-Enhanced MRI.

Objective: We aimed to propose an automatic method based on Support Vector Machine (SVM) and Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) to segment the tumor lesions of head and neck cancer (HNC). Materials and Methods: 120 DCE-MRI samples were collected. Five curve features and two principal components of the normalized time-intensity curve (TIC) in 80 samples were calculated as the dataset in training three SVM classifiers. The other 40 samples were used as the testing dataset. The area overlap measure (AOM) and the corresponding ratio (CR) and percent match (PM) were calculated to evaluate the segmentation performance. The training and testing procedure was repeated for 10 times, and the average performance was calculated and compared with similar studies. Results: Our method has achieved higher accuracy compared to the previous results in literature in HNC segmentation. The average AOM with the testing dataset was 0.76 ± 0.08, and the mean CR and PM were 79 ± 9% and 86 ± 8%, respectively. Conclusion: With improved segmentation performance, our proposed method is of potential in clinical practice for HNC.