Lignin-first fractionation has become a new biorefinery target to obtain valuable lignin monomers toward the complete utilization of lignocellulosic biomass, but increasing delignification through ...conventional pretreatment approaches often affects the structural integrity of the dissociated lignin. We discovered a new reactive lignin with a great solvent solubility and preserved β-O-4 linkages from eucalyptus after a modified organosolv pretreatment using 1,4-butanediol (1,4-BDO). Unlike conventional organosolv pretreatment using ethanol, lignin deposition was not observed in 1,4-BDO pretreatment. Meanwhile, 2D HSQC NMR analysis revealed that the residual lignin obtained from 1,4-BDO pretreated eucalypts contained a relatively higher amount of β-O-4 interunit linkages, indicating its higher integrity than ethanol pretreated lignin. This result agreed with the lower content of phenolic hydroxyl groups in dissolved lignin
via
31
P NMR analysis. With increasing pretreatment severity, the amount of aliphatic hydroxyl groups decreased in ethanol pretreated lignin while it remained at a higher level in 1,4-BDO pretreated lignin. These results suggested that 1,4-BDO quenched the benzyl carbocation intermediate and formed ether linkages with a hydroxyl tail at the α position of the lignin. Solubility tests revealed that grafting aliphatic hydroxyl groups on 1,4-BDO lignin increased its dissolution. This phenomenon was further demonstrated for four different diols with similar structures. In addition, more than 90% cellulose conversion was obtained for all the diol pretreated eucalyptus after 48 h of enzymatic hydrolysis with cellulase at a loading of 7.5 FPU per gram of glucan. Diol pretreatment thus offers a promising reaction pathway to coincide with three pillars of biorefinery for lignin fractionation, lignin structural integrity, and cellulose hydrolysis.
α-Etherification in diol pretreatment quenched lignin intermediate and produced a reactive lignin with hydroxyl tails. Hydroxyl tails increased lignin solubilization without cleavage of β-O-4 ether linkages.
Objective
To obtain attenuation-corrected PET images directly from non-attenuation-corrected images using a convolutional encoder-decoder network.
Methods
Brain PET images from 129 patients were ...evaluated. The network was designed to map non-attenuation-corrected (NAC) images to pixel-wise continuously valued measured attenuation-corrected (MAC) PET images via an encoder-decoder architecture. Image quality was evaluated using various evaluation metrics. Image quantification was assessed for 19 radiomic features in 83 brain regions as delineated using the Hammersmith atlas (n30r83). Reliability of measurements was determined using pixel-wise relative errors (RE; %) for radiomic feature values in reference MAC PET images.
Results
Peak signal-to-noise ratio (PSNR) and structural similarity index metric (SSIM) values were 39.2 ± 3.65 and 0.989 ± 0.006 for the external validation set, respectively. RE (%) of SUV
mean
was − 0.10 ± 2.14 for all regions, and only 3 of 83 regions depicted significant differences. However, the mean RE (%) of this region was 0.02 (range, − 0.83 to 1.18). SUV
max
had mean RE (%) of − 3.87 ± 2.84 for all brain regions, and 17 regions in the brain depicted significant differences with respect to MAC images with a mean RE of − 3.99 ± 2.11 (range, − 8.46 to 0.76). Homogeneity amongst Haralick-based radiomic features had the highest number (20) of regions with significant differences with a mean RE (%) of 7.22 ± 2.99.
Conclusions
Direct AC of PET images using deep convolutional encoder-decoder networks is a promising technique for brain PET images. The proposed deep learning method shows significant potential for emission-based AC in PET images with applications in PET/MRI and dedicated brain PET scanners.
Key Points
• We demonstrate direct emission-based attenuation correction of PET images without using anatomical information.
• We performed radiomics analysis of 83 brain regions to show robustness of direct attenuation correction of PET images.
• Deep learning methods have significant promise for emission-based attenuation correction in PET images with potential applications in PET/MRI and dedicated brain PET scanners.
Sensing surroundings plays a crucial role in human spatial perception, as it extracts the spatial configuration of objects as well as the free space from the observations. To facilitate the robot ...perception with such a surrounding sensing capability, we introduce a novel visual task called Cross-view Semantic Segmentation as well as a framework named View Parsing Network (VPN) to address it. In the cross-view semantic segmentation task, the agent is trained to parse the first-view observations into a top-down-view semantic map indicating the spatial location of all the objects at pixel-level. The main issue of this task is that we lack the real-world annotations of top-down-view data. To mitigate this, we train the VPN in 3D graphics environment and utilize the domain adaptation technique to transfer it to handle real-world data. We evaluate our VPN on both synthetic and real-world agents. The experimental results show that our model can effectively make use of the information from different views and multi-modalities to understanding spatial information. Our further experiment on a LoCoBot robot shows that our model enables the surrounding sensing capability from 2D image input. Code and demo videos can be found at https://view-parsing-network.github.io.
This article presents an auto-polarity thermoelectric energy-harvesting interface circuit based on a single-inductor boost/buck-boost hybrid converter. The power stage is configured automatically as ...a boost converter for a positive input voltage or a buck-boost converter for a negative input voltage. A collaborative efficiency-improving scheme of frequency selection and maximum power point tracking (MPPT) is implemented for input power ranging from 1 to 800 <inline-formula> <tex-math notation="LaTeX">\mu \text{W} </tex-math></inline-formula>. An improved digital zero-current detection (ZCD) technique with fast searching is proposed to turn off power switches accurately. Dual-polarity cold startup is realized with the aid of a pair of cross-coupled Dickson charge pumps. This work is fabricated with a 0.13-<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> CMOS process. From the measured results, the interface starts up from a 140- or −160-mV thermoelectric generator (TEG) voltage. It boosts input voltages ranging from 10 mV to 0.4 V and from −10 mV to −0.4 V to a 1.2-V output voltage. It achieves a peak end-to-end efficiency of 90% with a 0.3-V input voltage or 88% with a −0.4-V input voltage. Moreover, end-to-end efficiencies are higher than 80% for input voltages from 90 mV to 0.4 V and from −110 mV to −0.4 V.
Colorectal cancer (CRC) has been proven to be highly reliant on arginine availability. Limiting arginine-rich foods or treating patients with arginine-depleting enzymes arginine deiminase (ADI) or ...arginase can suppress colon cancer. However, arginase and ADI are not the best drug candidates for CRC. Ornithine, the product of arginase, can enhance the supply of polyamine, which favors CRC cell growth, while citrulline, the product of ADI, faces the problem of arginine recycling due to the overexpression of argininosuccinate synthetase (ASS). Biosynthetic arginine decarboxylase (ADC), an enzyme that catalyzes the conversion of arginine to agmatine and carbon dioxide, may be a better choice as it combines both arginine depletion and suppression of intracellular polyamine synthesis via its product agmatine. ADC has anti-tumor potential yet has received much less attention than the other two arginine-depleting enzymes. In order to gain a better understanding of ADC, the preparation and the anti-cancer properties of this enzyme were explored in this study. When tested in vitro, ADC inhibited the proliferation of three colorectal cancer cell lines regardless of their ASS cellular expression. In contrast, ADC had a lesser cytotoxic effect on the human foreskin fibroblasts and rat primary hepatocytes. Further in vitro studies revealed that ADC induced S and G2/M phase cell-cycle arrest and apoptosis in HCT116 and LoVo cells. ADC-induced apoptosis in HCT116 cells followed the mitochondrial apoptotic pathway and was caspase-3-dependent. With all results obtained, we suggest that arginine is a potential target for treating colorectal cancer with ADC, and the anti-cancer properties of ADC should be more deeply investigated in the future.
Objective: To externally validate the use of the Oakland score in identification of low-risk lower gastrointestinal bleeding patients who can be safely managed without hospitalisation in an accident ...and emergency department in Hong Kong.
Methods: This single-centre retrospective cohort study included adult patients who attended the accident and emergency department for lower gastrointestinal bleeding and were subsequently admitted to hospital from 1 January 2020 to 31 December 2020. Safe discharge was defined as absence of all of the following adverse outcomes after hospital presentation: blood transfusion; therapeutic colonoscopy, mesenteric embolisation, or laparotomy for bleeding; in-hospital death (all causes); and readmission with subsequent lower gastrointestinal bleeding within 28 days. The sensitivities, specificities and area under the receiver-operating characteristic curve of the Oakland score were calculated.
Results: Among 376 patients who were included in this study, 114 (30.3%) of them experienced one or more adverse outcomes. The area under the receiver-operating characteristic curve for safe discharge was 0.88 (95% confidence interval, 0.84-0.91). Using an Oakland score threshold of ⩽8 points as in the original derivation study can achieve 100% sensitivity (95% confidence interval, 96.8%-100%) and 7.3% specificity (95% confidence interval, 4.4%-11.1%) for safe discharge. When the Oakland score threshold was extended to ⩽11 points, a much greater proportion of low-risk patients could be identified, with 97.4% sensitivity (95% confidence interval, 92.5%-99.5%) and 32.8% specificity (95% confidence interval, 27.2%-38.9%) for safe discharge.
Conclusion: The Oakland score performed well in identification of lower gastrointestinal bleeding patients who were at low risk of experiencing adverse outcomes and could thus be safely managed without hospitalisation. Extension of the Oakland score threshold to ⩽11 points can allow identification of a greater proportion of low-risk patients while sensitivity is reasonably maintained.
A cyclometalated iridium complex is shown to catalyse the transfer hydrogenation of various nitrogen heterocycles, including but not limited to quinolines, isoquinolines, indoles and pyridinium ...salts, in an aqueous solution of HCO2H/HCO2Na under mild conditions. The catalyst shows excellent functional‐group compatibility and high turnover number (up to 7500), with catalyst loadings as low as 0.01 mol % being feasible. Mechanistic investigation of the quinoline reduction suggests that the transfer hydrogenation proceeds via both 1,2‐ and 1,4‐addition pathways, with the catalytic turnover being limited by the step of hydride transfer.
An easily accessible iridicycle catalyst effects the transfer hydrogenation of a wide variety of N‐heterocycles in water, including quinolines, isoquinolines, indoles, quinoxalines, and pyridines. The catalyst shows excellent functional‐group compatibility and high turnover number (up to 7500), even with low catalyst loadings.
Abstract
Objective
The aim of this study was to develop a deep learning algorithm for detection of active inflammatory sacroiliitis in short tau inversion recovery (STIR) sequence MRI.
Methods
A ...total of 326 participants with axial SpA, and 63 participants with non-specific back pain (NSBP) were recruited. STIR MRI of the SI joints was performed and clinical data were collected. Region of interests (ROIs) were drawn outlining bone marrow oedema, a reliable marker of active inflammation, which formed the ground truth masks from which ‘fake-colour’ images were derived. Both the original and fake-colour images were randomly allocated into either the training and validation dataset or the testing dataset. Attention U-net was used for the development of deep learning algorithms. As a comparison, an independent radiologist and rheumatologist, blinded to the ground truth masks, were tasked with identifying bone marrow oedema in the MRI scans.
Results
Inflammatory sacroiliitis was identified in 1398 MR images from 228 participants. No inflammation was found in 3944 MRI scans from 161 participants. The mean sensitivity of the algorithms derived from the original dataset and fake-colour image dataset were 0.86 (0.02) and 0.90 (0.01), respectively. The mean specificity of the algorithms derived from the original and the fake-colour image datasets were 0.92 (0.02) and 0.93 (0.01), respectively. The mean testing dice coefficients were 0.48 (0.27) for the original dataset and 0.51 (0.25) for the fake-colour image dataset. The area under the curve of the receiver operating characteristic (AUC-ROC) curve of the algorithms using the original dataset and the fake-colour image dataset were 0.92 and 0.96, respectively. The sensitivity and specificity of the algorithms were comparable with the interpretation by a radiologist, but outperformed that of the rheumatologist.
Conclusion
An MRI deep learning algorithm was developed for detection of inflammatory sacroiliitis in axial SpA.
As a form of social movement aiming to effect social change, protests could bring about unintended impacts on all walks of life. In other words, the cost of protests can be incurred by those who ...might not be protesters. The protests triggered by an extradition bill in Hong Kong since 2019 are no exception. This paper focuses on the impacts on the ridership of the metro system on protest days. It synthesizes and hypothesizes factors influencing the distribution of the ridership changes and conducts an empirical study in the context of Hong Kong to study the possible influences and spatial dependence. It is found that, across metro stations, political orientation (percentage of votes to pro-democracy camp in the 2019 Election of District Councils), law enforcement (permission from the police to protest), land use type (especially for commercial and open space), population age and income, as well as transit/road network characteristics and intermodal connectivity, significantly influence the ridership of metro stations during protest days. In addition, the mixed regressive spatial autoregressive model has higher explanatory power than the ordinary least square model, suggesting the need for a spatial lag and error specification. The results could also have significant implications for policy and planning for operating metro services and managing metro stations before, during, and after social shocks.
Objective
To determine the effectiveness of nurse‐led consultations in patients with stable rheumatoid arthritis (RA) in Hong Kong.
Methods
The present work was a single‐center, randomized, ...open‐label, noninferiority trial. Patients who had rheumatoid arthritis (RA) with low disease activity (LDA) were randomized at a 1:1 ratio to attend a nurse‐led consultation or rheumatologist follow‐up visit for 2 years. The primary end point was the proportion of patients whose RA remained at LDA. Secondary end points included the proportion of patients with RA in disease remission and the scores recorded on the Leeds Satisfaction Questionnaire at 2 years, changes from baseline on the Disease Activity Score in 28 joints using the C‐reactive protein level (DAS28‐CRP), modified Sharp/van der Heijde score (SHS), Health Assessment Questionnaire disability index (HAQ DI), Short Form 36 (SF‐36) physical component score, and 19‐item Compliance Questionnaire for Rheumatology (CQR‐19) score.
Results
Among 280 patients who were randomized equally to either attend nurse‐led consultations or rheumatologist follow‐up visits, 267 patients completed the study. In the nurse‐led consultation and rheumatologist follow‐up groups, 92.1% and 91.4% patients, respectively, remained at LDA at 2 years. The 95% confidence intervals (95% CIs) of the adjusted treatment difference were within the predefined noninferiority margin in both the intention‐to‐treat analysis (95% CI 5.75, 7.15) and the per‐protocol analysis (95% CI 1.67, 7.47). Although the changes in DAS28‐CRP score over 2 years were significantly different between the 2 treatment groups (P < 0.001), there were no significant changes from baseline in SHS, HAQ DI, SF‐36 physical component scores, and CQR‐19 scores. At the end of the study, more patients expressed satisfaction with nurse‐led consultations.
Conclusion
Nurse‐led consultations were not inferior to rheumatologist follow‐up visits in patients with stable RA.
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