Productive scientists are associated with lower disruption in scientific publishing.

While scientific researchers often aim for high productivity, prioritizing the quantity of publications may come at the cost of time and effort dedicated to individual research. It is thus important to examine the relationship between productivity and disruption for individual researchers. Here, we show that with the increase in the number of published papers, the average citation per paper will be higher yet the mean disruption of papers will be lower. In addition, we find that the disruption of scientists' papers may decrease when they are highly productive in a given year. The disruption of papers in each year is not determined by the total number of papers published in the author's career, but rather by the productivity of that particular year. Besides, more productive authors also tend to give references to recent and high-impact research. Our findings highlight the potential risks of pursuing productivity and aim to encourage more thoughtful career planning among scientists.

Equirectangular Image Data Detection, Segmentation and Classification of Varying Sized Traffic Signs: A Comparison of Deep Learning Methods.

There are known limitations in mobile omnidirectional camera systems with an equirectangular projection in the wild, such as momentum-caused object distortion within images, partial occlusion and the effects of environmental settings. The localization, instance segmentation and classification of traffic signs from image data is of significant importance to applications such as Traffic Sign Detection and Recognition (TSDR) and Advanced Driver Assistance Systems (ADAS). Works show the efficacy of using state-of-the-art deep pixel-wise methods for this task yet rely on the input of classical landscape image data, automatic camera focus and collection in ideal weather settings, which does not accurately represent the application of technologies in the wild. We present a new processing pipeline for extracting objects within omnidirectional images in the wild, with included demonstration in a Traffic Sign Detection and Recognition (TDSR) system. We compare Mask RCNN, Cascade RCNN, and Hybrid Task Cascade (HTC) methods, while testing RsNeXt 101, Swin-S and HRNetV2p backbones, with transfer learning for localization and instance segmentation. The results from our multinomial classification experiment show that using our proposed pipeline, given that a traffic sign is detected, there is above a 95% chance that it is classified correctly between 12 classes despite the limitations mentioned. Our results on the projected images should provide a path to use omnidirectional images with image processing to enable the full surrounding awareness from one image source.

Muricauda chongwuensis sp. nov., isolated from coastal seawater of China.

In the course of screening for bacterial predators, a Gram-stain-negative, non-flagellated, gliding, long rod-shaped, and yellow-pigmented bacterium, designated strain HICWT, was isolated from coastal seawater of China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain HICWT represented a member of the genus Muricauda and showed the highest sequence similarity to M. aquimarina JCM11811T (98.8%) and M. ruestringensis DSM13258T (98.1%). The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between strain HICWT and M. aquimarina JCM11811T were 79.2% and 34.1%, respectively. NaCl was required for growth. Optimum growth occurred at 25-30 °C, 2.0-3.0% (w/v) NaCl with pH 7.0. Strain HICWT showed some similar characteristics to the nonobligate bacterial predators, and the cells can attach to the prey cells. Strain HICWT contained MK-6 as the predominant respiratory quinone and had iso-C15:0, iso-C15:1 G, and iso-C17:0 3-OH as the major cellular fatty acids. The polar lipids contained phosphatidylethanolamine (PE), three unidentified phospholipids (PL1-PL3), one unidentified amino lipids (AL), and three unidentified polar lipids (L1-L3). The genome size of strain HICWT was approximately 3.8 Mbp, with a G + C content of 41.4%. Based on the polyphasic evidence, strain HICWT is proposed as representing a new species of the genus Muricauda, for which the name Muricauda chongwuensis sp. nov. is proposed. The type strain is HICWT (= JCM 33643 T = MCCC 1K03769T).

Anti-Ageing Effect of Physalis alkekengi Ethyl Acetate Layer on a d-galactose-Induced Mouse Model through the Reduction of Cellular Senescence and Oxidative Stress.

We aimed to study the effects of an ethyl acetate fraction of Physalis alkekengi (PAE) on d-galactose (d-gal)-induced senescence and the underlying mechanism. Firstly, analysis of the phytochemical composition revealed total flavonoids, total phenolics, total saponins, rutin, and luteolin contents of 71.72 ± 2.99 mg rutin equivalents/g, 40.19 ± 0.47 mg gallic acid equivalents/g, 128.13 ± 1.04 mg oleanolic acid equivalents/g, 1.67 ± 0.07 mg/g and 1.61 ± 0.01 mg/g, respectively. The mice were treated with d-gal for six weeks, and from the fifth week, the mice were administered with PAE by gavage once a day for five weeks. We found significant d-gal-induced ageing-related changes, such as learning and memory impairment in novel object recognition and Y-maze, fatigue in weight-loaded forced swimming, reduced thymus coefficient, and histopathological injury of the liver, spleen, and hippocampus. The PAE effectively protected from such changes. Further evaluation showed that PAE decreased the senescence-associated ß-galactosidase of the liver, spleen, and hippocampus, as well as the oxidative stress of the liver, plasma, and brain. The abundance of flavonoids, phenols, and saponins in PAE may have contributed to the above results. Overall, this study showed the potential application of PAE for the prevention or treatment of ageing-associated disorders.

Hydrofluoric acid-based etching effect on surface pit, crack, and scratch and laser damage site of fused silica optics.

In a large-scale, high-power laser facility, fused silica optics plays an irreplaceable role to transmit extremely intense lasers. However, the surface fractures, such as surface pit, crack, and scratch and laser damage site, of fused silica optics will shorten the lifetime of the optics and thus limit the output performance of the laser facility. In this work, besides experimental study, finite difference time domain (FDTD) simulation is performed to study hydrofluoric acid-based (HF-based) etching effect on the surface fractures. The effect of local surface curvature on etching rate is discussed and an explicit local-curvature-dependent etching model is proposed. Based on this model, the result from FDTD simulation qualitatively agrees very well with that of the experiment. It is demonstrated that the FDTD simulation is efficient to predict the morphological evolution of the surface fractures during etching. In addition, it is found that the surface fractures will be passivated and HF-based etching can greatly suppress the laser-damage growth of laser-induced damage to the surface site of fused silica optics.

Halobacteriovorax vibrionivorans sp. nov., a novel prokaryotic predator isolated from coastal seawater of China.

Three prokaryotic predator strains, BL9T, BL10 and BL28, were isolated with Vibrio alginolyticus from coastal seawater of PR China. Cells of the strains were Gram-negative, vibrioid-shaped and motile with a single sheathed flagellum (25-28 nm wide). Cells were around 0.3×0.5-1.0 µm in size. The three strains were obligate predators that exhibited a biphasic life cycle: a free-swimming attack phase and an intraperiplasmic growth phase within the prey. Bdelloplasts were formed. NaCl was required for growth. Optimum growth occurred at ~37 °C, with 2-4 % (w/v) NaCl and at pH 7.0-8.0. The results of phylogenetic analyses based on 16S rRNA gene sequences indicated that the three strains shared 99.9 % similarity to each other, were affiliated with the genus Halobacteriovorax in the class Oligoflexia, and represented the same new species. Strain BL9T (=MCCC 1K03527T=JCM 32962T) was designated as the type strain. Genome sequencing of strain BL9T revealed a genome size of 3.14 Mb and a G+C content of 35.8 mol%. The estimated digital DNA-DNA hybridization (dDDH) values and the whole genome average nucleotide identity (gANI) values between the genome of strain BL9T and those of Bdellovibrionales and Bacteriovoracales were 12.5-19 and 63.49-76.15 %, respectively. On the basis of life cycle features, results of physiological analyses, gANI data and dDDH data, strain BL9T represents a new species within the genus Halobacteriovorax, for which the name Halobacteriovoraxvibrionivorans sp. nov. is proposed.

Quantifying the accuracy of ancestral state prediction in a phylogenetic tree under maximum parsimony.

In phylogenetic studies, biologists often wish to estimate the ancestral discrete character state at an interior vertex v of an evolutionary tree T from the states that are observed at the leaves of the tree. A simple and fast estimation method-maximum parsimony-takes the ancestral state at v to be any state that minimises the number of state changes in T required to explain its evolution on T. In this paper, we investigate the reconstruction accuracy of this estimation method further, under a simple symmetric model of state change, and obtain a number of new results, both for 2-state characters, and r-state characters ([Formula: see text]). Our results rely on establishing new identities and inequalities, based on a coupling argument that involves a simpler 'coin toss' approach to ancestral state reconstruction.

Linear iterative near-field phase retrieval (LIPR) for dual-energy x-ray imaging and material discrimination.

Near-field x-ray refraction (phase) contrast is unavoidable in many lab-based micro-CT imaging systems. Quantitative analysis of x-ray refraction (a.k.a. phase retrieval) is in general an under-constrained problem. Regularizing assumptions may not hold true for interesting samples; popular single-material methods are inappropriate for heterogeneous samples, leading to undesired blurring and/or over-sharpening. In this paper, we constrain and solve the phase-retrieval problem for heterogeneous objects, using the Alvarez-Macovski model for x-ray attenuation. Under this assumption we neglect Rayleigh scattering and pair production, considering only Compton scattering and the photoelectric effect. We formulate and test the resulting method to extract the material properties of density and atomic number from single-distance, dual-energy imaging of both strongly and weakly attenuating multi-material objects with polychromatic x-ray spectra. Simulation and experimental data are used to compare our proposed method with the Paganin single-material phase-retrieval algorithm, and an innovative interpretation of the data-constrained modeling phase-retrieval technique.

Microvascular Decompression for Trigeminal Neuralgia Due to Venous Compression Alone.

Microvascular decompression (MVD) has been confirmed as an effective treatment of trigeminal neuralgia (TN); however, most previous reports just focused on MVD for TN caused by arterial conflict, there is a paucity of information about its use in venous compression causing TN. In the present study, the authors summarize 5-year experience of MVD for primary TN due to venous compression alone. Thirty-four patients with primary TN caused solely by veins underwent MVD. The presenting symptoms, key operative notes, surgical outcomes together with complications were reviewed. Of all the 34 patients, 19 (55.9%) patients occurred as typical TN. The V2 division was the most commonly affected area. Most of the venous conflicts were grade III (20/34, 58.8%). Deep superior petrosal venous system was the most frequent offending vessel (21/34, 61.8%). The venous conflicts were located at the trigeminal root entry zone in 10 (29.4%) patients, the mid cisternal zone in 18 (52.9%) patients, and the porus of Meckel's cave in 11 (32.4%) patients. At the last follow-up, excellent outcome was obtained in 26 (76.5%) patients, 7 (20.6%) patients got good outcome, fair outcome was achieved in 7 (20.6%) patients, and 1 patient unimproved (2.9%). Cerebrospinal fluid leakage was the most common complication (5.9%). In conclusion, MVD is a safe and effective surgical option for TN due to venous compression alone. It is noteworthy to explore the entire nerve and to protect veins as much as possible.

Branch lengths on birth-death trees and the expected loss of phylogenetic diversity.

Diversification is nested, and early models suggested this could lead to a great deal of evolutionary redundancy in the Tree of Life. This result is based on a particular set of branch lengths produced by the common coalescent, where pendant branches leading to tips can be very short compared with branches deeper in the tree. Here, we analyze alternative and more realistic Yule and birth-death models. We show how censoring at the present both makes average branches one half what we might expect and makes pendant and interior branches roughly equal in length. Although dependent on whether we condition on the size of the tree, its age, or both, these results hold both for the Yule model and for birth-death models with moderate extinction. Importantly, the rough equivalency in interior and exterior branch lengths means that the loss of evolutionary history with loss of species can be roughly linear. Under these models, the Tree of Life may offer limited redundancy in the face of ongoing species loss.

[Isolation, identification and characterization of 68 protease-producing bacterial strains from the Arctic].

OBJECTIVE: We screened and identified protease-producing bacterial strains from the Arctic, the results would help find cold-adapted protease. METHODS: In total 68 protease-producing strains were screened from the Arctic using the casein-agar plate under low temperature. All strains were classified using the 16S rRNA gene-restriction fragment length polymorphism (RFLP) and traditional phenotypic test. One strain was chosen to be the representative strain from each group respectively and identified using 16S rRNA gene sequence analysis, GenBank database Basic Local Alignment Search Tool (BLAST), phylogenetic analysis and phenotypic features analysis. The enzymatic properties of the representative strains were determined. RESULTS: The 68 strains belonged to 3 groups (54.41%, 42.65% and 2.94%), and strains 6, 11 and 52 were the representative strains respectively. The results of the 16S rRNA gene sequence analysis showed that: Strain 11 was most closely related to Chryseobacterium scophthalmum with 98.24% sequence similarity; strain 52 was most closely related to Stenotrophomonas rhizophila with 98.55% sequence similarity; strain 6 was most closely related to Stenotrophomonas rhizophila with 96.50% sequence similarity, which might represent a novel species of the genus. The phenotypic study showed that: strains 6, 11 and 52 were Gram negative, straight rod-shaped, did not produce extracellular lipase and amylase, possessed strong proteolytic activity. The optimal temperature and pH for the enzyme activity were 55 degrees C and 6.7 for the protease from strain 6, 40 degrees C and 8.5 for the protease from strain 11 and 65 degrees C and 7.4 for the protease from strain 52. CONCLUSION: The research firstly introduced the distribution of Stenotrophomonas and Chryseobacterium specieses in the Arctic marine water, extended the diversity of the protease-producing bacteria from the Arctic, and provided a useful basis for further study of cold-adapted protease.

Quantitative Identification of ADHD Tendency in Children With Immersive Fingertip Force Control Tasks.

Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder that affects children. However, the traditional scale-based diagnosis methods rely more on subjective experiences, leading to a demand of objective biomarkers and quantified diagnostic methods. This study proposes a quantitative approach for identifying ADHD tendency based on fingertip pressing force control paradigm with immersive visual feedback. By extracting nine behavioral features from reaction time and dynamic force fluctuation features with high temporal and amplitude resolution, the proposed method can effectively capture the continuous changes in attention levels for ADHD diagnosis. The extracted features were analyzed using independent sample t-test and Pearson correlation to determine their association with ADHD-RS scale scores. Results showed that 12 statistical indicators were effective for distinguishing ADHD children from typically developed children, and several features of force control ability were also associated with core ADHD symptoms. A support vector machine (SVM) based classifier is trained for ADHD diagnosis and achieved an accuracy of 78.5%. This work provides an objective and quantitative approach for identifying ADHD tendency within a short testing time, and reveals the inherent correlation between the attention levels and the extracted features of reaction time and force fluctuation dynamics.

[Composition and distribution of TCBS bacteria groups from sediments of Jiulong River estuary].

OBJECTIVE: To investigate potential pathogens in waters of Xiamen from Jiulong River, and to provide useful information for the prevention and control of potential pathogen infections. METHODS: All samples were spread on Thiosulfate Citrate Bile Salts Sucrose (TCBS) agar plates, and then incubated at 26 +/- 1 degrees C for 24 +/- 2 h. In total 158 TCBS strains were isolated from TCBS agar plates and pure-cultivated on 2216E agar plates. All strains were identified using the 16S rRNA gene- Restriction fragment length polymorphism (RFLP), 16S rRNA sequence analysis, GenBank database Basic Local Alignment Search Tool (BLAST) and phylogenetic analysis. RESULTS: The results show that 158 TCBS strains from the sediments of Jiulong River estuary were classfied as 7 genus, which were Pseudomonas (28%), Aeromonas (24%), Pseudoalteromonas (19%), Shewanella (13%), Bacillus (11%), Vibrio (4%) and Psychrobacter (1%). The composition and distribution of TCBS bacteria groups varied with stations. Non-halophilic or haloduric bacteria groups were dominant in the upper area of Jiulong River estuary, and halophilic and haloduric bacteria were dominant in the lower area, which characterized a typical estuary feature. The salinity played a key role in the distribution of TCBS groups. Vibrios did not constitute a significant proportion (6% - 19%) of the total TCBS strains at different stations, and most of the them distributed at the lower region. CONCLUSION: There were a lot of potential pathogens in Jiulong River estuary. Aeromonas, a typical genus of halotolerant bacteria, was the potentially terrigenous bacteria contamination to the waters of Xiamen. Most Vibrio specieses were marine aborigines, which was not directly contaminated from the runoff of Jiulong River.

MicroRNA-1269 is downregulated in glioblastoma and its maturation is regulated by long non-coding RNA SLC16A1 Antisense RNA 1.

MicroRNA-1269 (miR-1296) promotes esophageal cancer. However, its role in other cancers, such as glioblastoma (GBM) is unclear. We predicted that miR-1269 might interact with long non-coding RNA (lncRNA) SLC16A1 Antisense RNA 1 (SLC16A1-AS1), a critical player in GBM. We then studied the interaction between SLC16A1-AS1 and miR-1269 in GBM. In this study, paired GBM and non-tumor tissues were used to analyze the expression of SLC16A1-AS1 and premature and mature miR-1269. The interaction of SLC16A1-AS1 with premature miR-1269 was analyzed with RNA pull-down assay and dual-luciferase reporter assay. Cellular fractionation assay was applied to determine the subcellular location of SLC16A1-AS1. Overexpression assays were applied to determine the role of SLC16A1-AS1 in miR-1269 maturation. BrdU, Transwell and cell apoptosis assays were performed to analyze the role of SLC16A1-AS1 and miR-1269 in GBM cell proliferation, migration, and invasion. Interestingly, we observed the upregulation of premature miR-1269 and downregulation of mature miR-1269 in GBM. SLC16A1-AS1 was also overexpressed in GBM. The direct interaction of SLC16A1-AS1 with premature miR-1269 was observed. SLC16A1-AS1 suppressed miR-1269 maturation and promoted cell proliferation, migration, and invasion, and inhibited cell apoptosis, while miR-1269 displayed the opposite trend. SLC16A1-AS1 partly reversed the effects of miR-1269 on GBM cell proliferation, movement and apoptosis. Moreover, SLC16A1-AS1 overexpression increased the level of ki-67, CDK4 and Bcl-2 in LN-229 and LN-18 cells. However, miR-1269 could partly reverse the effect of SLC16A-AS1 on protein levels. Overall, miR-1269 is downregulated in GBM and its maturation is regulated by SLC16A1-AS1.

Size-dependent effects of polystyrene nanoplastics on autophagy response in human umbilical vein endothelial cells.

Ubiquitous nanoplastics (NPs) increase exposure risks to humans through the food chain and/or other ways. However, huge knowledge gaps exist regarding the fate and adverse impact of NPs on the human cardiovascular system. Autophagy is an important catabolic pathway that disposes of cytoplasmic waste through the lysosomes. In this study, we pursued to determine the interaction and autophagy effect of polystyrene nanoplastics (PS-NPs) (100 and 500 nm in size) on human umbilical vein endothelial cells (HUVECs). The results showed both sizes of PS-NPs interacted with almost all the treated HUVECs in a time- and concentration-dependent manner, and 500 nm PS-NPs were only bound to the surface of cell membranes, whereas 100 nm PS-NPs were taken up by HUVECs and aggregated in the cytoplasm. Furthermore, exposure to 25 µg/mL of 500 nm PS-NPs for 48 h significantly increased lactate dehydrogenase release from HUVECs, while internalized 100 nm PS-NPs not only caused cell membrane damage, but also induced autophagy initiation and autophagosome formation. By a mCherry-GFP-LC3 lentivirus infection assay, we also demonstrated that autophagic flux level was impaired in response to 100 nm PS-NPs. Herein, our results provide new insight into the size-dependent internalization and autophagy response to PS-NPs in HUVECs.

Dark-field tomography of an attenuating object using intrinsic x-ray speckle tracking.

Purpose: We investigate how an intrinsic speckle tracking approach to speckle-based x-ray imaging is used to extract an object's effective dark-field (DF) signal, which is capable of providing object information in three dimensions. Approach: The effective DF signal was extracted using a Fokker-Planck type formalism, which models the deformations of illuminating reference beam speckles due to both coherent and diffusive scatter from the sample. Here, we assumed that (a) small-angle scattering fans at the exit surface of the sample are rotationally symmetric and (b) the object has both attenuating and refractive properties. The associated inverse problem of extracting the effective DF signal was numerically stabilized using a "weighted determinants" approach. Results: Effective DF projection images, as well as the DF tomographic reconstructions of the wood sample, are presented. DF tomography was performed using a filtered back projection reconstruction algorithm. The DF tomographic reconstructions of the wood sample provided complementary, and otherwise inaccessible, information to augment the phase contrast reconstructions, which were also computed. Conclusions: An intrinsic speckle tracking approach to speckle-based imaging can tomographically reconstruct an object's DF signal at a low sample exposure and with a simple experimental setup. The obtained DF reconstructions have an image quality comparable to alternative x-ray DF techniques.

Distribution of Vibrio alginolyticus-like species in Shenzhen coastal waters, China.

We investigated the distribution of vibrios in Shenzhen coastal waters in order to obtain valuable information for the aquaculture industry and a health warning system. Quantities of vibrios from surface waters ranged from 0 to 4.40×10(4) CFUs mL(-1) in April (spring), while from 0 to 2.57×10(3) CFUs mL(-1) in September (autumn); the abundance of V. alginolyticus-like species from surface water ranged from 0 to 6.72×10(3) CFUs mL(-1) in April (spring) and from 0 to 1.28×10(3) CFUs mL(-1) in September (autumn); higher counts were observed in spring. The V. alginolyticus-like species was dominant in Shenzhen coastal waters, with the highest abundance in the clean region (stations YMK001 and GDN064) in April, suggesting that Vibrio spp. were naturally occurring bacteria in marine environments. The correlation between the abundance of vibrios (including V. alginolyticus-like species) and environmental factors varied in different regions and different seasons. There were no vibrios detected when the salinity was less than 11.15‰ in the Zhujiang River estuary, which indicated that salinity played a key role in the distribution of vibrios and V. alginolyticus-like species.

LncRNA SLC16A1-AS1 is Upregulated in Glioblastoma and Promotes Cancer Cell Proliferation by Regulating miR-149 Methylation.

INTRODUCTION: LncRNA SLC16A1-AS1 has been characterized as a critical player in lung cancer, while its role in glioblastoma (GBM) is unknown. By analyzing the TCGA dataset, we observed the upregulation of SLC16A1-AS1 expression in GBM. Therefore, we aimed to investigate the role of SLC16A1-AS1 in this cancer. METHODS: GBM tissues and paired non-tumor tissues were collected from 62 GBM patients through biopsy. RT-qPCR was performed to determine the expression of SLC16A1-AS1 and miR-149. Linear regression was used to analyze their correlations. The relationship between SLC16A1-AS1 and miR-149 was assessed by gain and loss of function experiments. Methylation-specific PCR (MSP) and bisulfite sequencing PCR (BSP) were performed to analyze the methylation status of miR-149. Cell proliferation was evaluated by CCK-8 assay and colony formation experiments in GBM cells. RESULTS: We found that SLC16A1-AS1 expression was upregulated in GBM tissues, and the upregulated expression of SLC16A1-AS1 predicted poor survival of GBM patients. MiR-149 was downregulated in GBM tissues and inversely correlated with the expression of SLC16A1-AS1. In GBM cells, overexpression of SLC16A1-AS1 downregulated the expression of miR-149 and increased the methylation of miR-149 gene. In cell proliferation and colony formation assay, overexpression of SLC16A1-AS1 reduced the inhibitory effects of miR-149 on GBM cell proliferation. CONCLUSION: SLC16A1-AS1 may promote GBM cell proliferation by regulating miR-149 methylation. SLC16A1-AS1 can be considered as a potential diagnostic marker in GBM.

Systematic profiling of SARS-CoV-2-specific IgG responses elicited by an inactivated virus vaccine identifies peptides and proteins for predicting vaccination efficacy.

One of the best ways to control COVID-19 is vaccination. Among the various SARS-CoV-2 vaccines, inactivated virus vaccines have been widely applied in China and many other countries. To understand the underlying protective mechanism of these vaccines, it is necessary to systematically analyze the humoral responses that are triggered. By utilizing a SARS-CoV-2 microarray with 21 proteins and 197 peptides that fully cover the spike protein, antibody response profiles of 59 serum samples collected from 32 volunteers immunized with the inactivated virus vaccine BBIBP-CorV were generated. For this set of samples, the microarray results correlated with the neutralization titers of the authentic virus, and two peptides (S1-5 and S2-22) were identified as potential biomarkers for assessing the effectiveness of vaccination. Moreover, by comparing immunized volunteers to convalescent and hospitalized COVID-19 patients, the N protein, NSP7, and S2-78 were identified as potential biomarkers for differentiating COVID-19 patients from individuals vaccinated with the inactivated SARS-CoV-2 vaccine. The comprehensive profile of humoral responses against the inactivated SARS-CoV-2 vaccine will facilitate a deeper understanding of the vaccine and provide potential biomarkers for inactivated virus vaccine-related applications.

Quantitative material decomposition using linear iterative near-field phase retrieval dual-energy x-ray imaging.

This paper expands the linear iterative near-field phase retrieval (LIPR) formalism to achieve quantitative material thickness decomposition. Propagation-based phase contrast x-ray imaging with subsequent phase retrieval has been shown to improve the signal-to-noise ratio (SNR) by factors of up to hundreds compared to conventional x-ray imaging. This is a key step in biomedical imaging, where radiation exposure must be kept low without compromising the SNR. However, for a satisfactory phase retrieval from a single measurement, assumptions must be made about the object investigated. To avoid such assumptions, we use two measurements collected at the same propagation distance but at different x-ray energies. Phase retrieval is then performed by incorporating the Alvarez-Macovski (AM) model, which models the x-ray interactions as being comprised of distinct photoelectric and Compton scattering components. We present the first application of dual-energy phase retrieval with the AM model to monochromatic experimental x-ray projections at two different energies for obtaining split x-ray interactions. Our phase retrieval method allows us to separate the object investigated into the projected thicknesses of two known materials. Our phase retrieval output leads to no visible loss in spatial resolution while the SNR improves by factors of 2 to 10. This corresponds to a possible x-ray dose reduction by a factor of 4 to 100, under the Poisson noise assumption.