Publications by authors named "Jae Sung Lee"

414 Publications

Quantitative salivary gland SPECT/CT using deep convolutional neural networks.

Sci Rep 2021 Apr 9;11(1):7842. Epub 2021 Apr 9.

Department of Nuclear Medicine, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Korea.

Quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) using Tc-99m pertechnetate aids in evaluating salivary gland function. However, gland segmentation and quantitation of gland uptake is challenging. We develop a salivary gland SPECT/CT with automated segmentation using a deep convolutional neural network (CNN). The protocol comprises SPECT/CT at 20 min, sialagogue stimulation, and SPECT at 40 min post-injection of Tc-99m pertechnetate (555 MBq). The 40-min SPECT was reconstructed using the 20-min CT after misregistration correction. Manual salivary gland segmentation for %injected dose (%ID) by human experts proved highly reproducible, but took 15 min per scan. An automatic salivary segmentation method was developed using a modified 3D U-Net for end-to-end learning from the human experts (n = 333). The automatic segmentation performed comparably with human experts in voxel-wise comparison (mean Dice similarity coefficient of 0.81 for parotid and 0.79 for submandibular, respectively) and gland %ID correlation (R = 0.93 parotid, R = 0.95 submandibular) with an operating time less than 1 min. The algorithm generated results that were comparable to the reference data. In conclusion, with the aid of a CNN, we developed a quantitative salivary gland SPECT/CT protocol feasible for clinical applications. The method saves analysis time and manual effort while reducing patients' radiation exposure.
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http://dx.doi.org/10.1038/s41598-021-87497-0DOI Listing
April 2021

Supplementing with L-Tryptophan Increases Medium Protein and Alters Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary Cells.

Int J Mol Sci 2021 Mar 9;22(5). Epub 2021 Mar 9.

Department of Animal Science and Technology, Konkuk University, Seoul 05029, Korea.

The objective of this study was to investigate the effects of supplementing with L-tryptophan (L-Trp) on milk protein synthesis using an immortalized bovine mammary epithelial (MAC-T) cell line. Cells were treated with 0, 0.3, 0.6, 0.9, 1.2, and 1.5 mM of supplemental L-Trp, and the most efficient time for protein synthesis was determined by measuring cell, medium, and total protein at 0, 24, 48, 72, and 96 h. Time and dose tests showed that the 48 h incubation time and a 0.9 mM dose of L-Trp were the optimal values. The mechanism of milk protein synthesis was elucidated through proteomic analysis to identify the metabolic pathway involved. When L-Trp was supplemented, extracellular protein (medium protein) reached its peak at 48 h, whereas intracellular cell protein reached its peak at 96 h with all L-Trp doses. β-casein mRNA gene expression and genes related to milk protein synthesis, such as mammalian target of rapamycin (mTOR) and ribosomal protein 6 (RPS6) genes, were also stimulated ( < 0.05). Overall, there were 51 upregulated and 59 downregulated proteins, many of which are involved in protein synthesis. The results of protein pathway analysis showed that L-Trp stimulated glycolysis, the pentose phosphate pathway, and ATP synthesis, which are pathways involved in energy metabolism. Together, these results demonstrate that L-Trp supplementation, particularly at 0.9 mM, is an effective stimulus in β-casein synthesis by stimulating genes, proteins, and pathways related to protein and energy metabolism.
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http://dx.doi.org/10.3390/ijms22052751DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7963161PMC
March 2021

Analysis of Fracture Characteristic and Medial Collateral Ligament Injury Relationships in Terrible Triad Elbow Injuries.

J Hand Surg Am 2021 Mar 29. Epub 2021 Mar 29.

Department of Radiation Oncology, Medical Center of Chung-Ang University School of Medicine, Seoul, Korea.

Purpose: The objectives of this study were to identify the relationship between fracture characteristics and medial collateral ligament (MCL) injuries in terrible triad injuries of the elbow.

Methods: Between 2010 and 2018, 60 patients who underwent surgery for terrible triad elbow injuries were retrospectively reviewed. Using magnetic resonance imaging (MRI) assessments, patients were stratified into those who had intact or low-grade partial MCL tears (low-grade MRI-MCL group) and those who had high-grade partial or full-thickness MCL tears (high-grade MRI-MCL group). We also analyzed patients according to whether they underwent MCL repair surgery. Fractures of the radial head were assessed according to Mason's classification system and measurements of fracture fragment arc on axial cuts. Fractures of the coronoid processes were assessed according to the system of Regan and Morrey and measurements of coronoid process volumes.

Results: Patients in the high-grade MRI-MCL group (28 patients) had a more comminuted and higher fragment arc of radial head fractures than those in the low-grade MRI-MCL group (32 patients) (143º ± 45º vs 119º ± 31º). However, the volume of coronoid fracture fragments was smaller in the high-grade MRI-MCL than in the low-grade MRI-MCL group (359 ± 325 mm vs 722 ± 448 mm). The MCL repair group (22 patients) also had a more comminuted and higher fragment arc in radial head fractures (153º ± 44º vs 117º ± 31º) and a smaller coronoid process fracture volume (236 ± 224 mm vs 735 ± 419 mm) than the non-MCL repair group (38 patients).

Conclusions: Our results demonstrated that high-grade MCL injuries are associated with comminuted and larger-sized radial head fractures, as well as smaller-sized coronoid process fractures in terrible triad injuries. In making a decision regarding surgical treatment, these fracture characteristics could help to predict the severity for MCL injury in terrible triad injuries.

Type Of Study/level Of Evidence: Prognostic IV.
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http://dx.doi.org/10.1016/j.jhsa.2021.01.015DOI Listing
March 2021

Anatomy-guided PET reconstruction usingbowsher prior.

Phys Med Biol 2021 Mar 29. Epub 2021 Mar 29.

Nuclear Medicine, Seoul National University, Seoul 03080, Korea, Seoul, 03080, Korea (the Republic of).

Advances in simultaneous positron emission tomography/magnetic resonance imaging (PET/MRI) technology have led to an active investigation of the anatomy-guided regularized PET image reconstruction algorithm based on MR images. Among the various priors proposed for anatomy-guided regularized PET image reconstruction, Bowsher's method based on second-order smoothing priors sometimes suffers from over-smoothing of detailed structures. Therefore, in this study, we propose a Bowsher prior based on thenorm and an iteratively reweighting scheme to overcome the limitation of the original Bowsher method. In addition, we have derived a closed solution for iterative image reconstruction based on this non-smooth prior. A comparison study between the originaland proposedBowsher priors was conducted using computer simulation and real human data. In the simulation and real data application, small lesions with abnormal PET uptake were better detected by the proposedBowsher prior methods than the original Bowsher prior. The originalBowsher leads to a decreased PET intensity in small lesions when there is no clear separation between the lesions and surrounding tissue in the anatomical prior. However, the proposedBowsher prior methods showed better contrast between the tumors and surrounding tissues owing to the intrinsic edge-preserving property of the prior which is attributed to the sparseness induced bynorm, especially in the iterative reweighting scheme. Besides, the proposed methods demonstrated lower bias and less hyper-parameter dependency on PET intensity estimation in the regions with matched anatomical boundaries in PET and MRI. Therefore, these methods will be useful for improving the PET image quality based on the anatomical side information.
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http://dx.doi.org/10.1088/1361-6560/abf2f7DOI Listing
March 2021

Performance Evaluation of SimPET-X, a PET Insert for Simultaneous Mouse Total-Body PET/MR Imaging.

Mol Imaging Biol 2021 Mar 25. Epub 2021 Mar 25.

Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea.

Purpose: In this study, a small animal PET insert (SimPET-X, Brightonix Imaging Inc.) for simultaneous PET/MR imaging studies is presented. This insert covers an 11-cm-long axial field-of-view (FOV) and enables imaging of mouse total-bodies and rat heads.

Procedures: SimPET-X comprises 16 detector modules to yield a ring diameter of 63 mm and an axial FOV of 110 mm. The detector module supports four detector blocks, each comprising two 4 × 4 SiPM arrays coupled with a 20 × 9 array of LSO crystals (1.2 × 1.2 × 10 mm). The physical characteristics of SimPET-X were measured in accordance with the NEMA NU4-2008 standard protocol. In addition, we assessed the compatibility of SimPET-X with a small animal-dedicated MRI (M7, Aspect Imaging) and conducted phantom and animal studies.

Results: The radial spatial resolutions at the center based on 3D OSEM without and with the warm background were 0.73 mm and 0.99 mm, respectively. The absolute peak sensitivity of the system was 10.44% with an energy window of 100-900 keV and 8.27% with an energy window of 250-750 keV. The peak NECR and scatter fraction for the mouse phantom were 348 kcps at 26.2 MBq and 22.1% with an energy window of 250-750 keV, respectively. The standard deviation of pixel value in the uniform region of an NEMA IQ phantom was 4.57%. The spillover ratios for air- and water-filled chambers were 9.0% and 11.0%, respectively. In the hot-rod phantom image reconstructed using 3D OSEM-PSF, all small rods were resolved owing to the high spatial resolution of the SimPET-X system. There was no notable interference between SimPET-X and M7 MRI. SimPET-X provided high-quality mouse images with superior spatial resolution, sensitivity, and counting rate performance.

Conclusion: SimPET-X yielded a remarkably improved sensitivity and NECR compared with SimPET.
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http://dx.doi.org/10.1007/s11307-021-01595-zDOI Listing
March 2021

Scalable electronic readout design for a 100 ps coincidence time resolution TOF-PET system.

Phys Med Biol 2021 Mar 24. Epub 2021 Mar 24.

Department of Radiology, Stanford University, Stanford, California, CA 94305-4075, UNITED STATES.

We have developed a scalable detector readout design for a 100 ps coincidence time resolution (CTR) time of flight (TOF) positron emission tomography (PET) detector technology. The basic scintillation detectors studied in this paper are based on 2×4 arrays of 3×3×10 mm³ "fast- LGSO:Ce" scintillation crystals side- coupled to 6×4 arrays of 3×3 mm² silicon photomultipliers (SiPMs). We employed a novel mixed-signal front-end electronic configuration and a low timing jitter Field Programming Gate Array (FPGA)-based time to digital converter (TDC) for data acquisition. Using a 22 Na point source, >10,000 coincidence events were experimentally acquired for several SiPM bias voltages, leading edge time-pickoff thresholds, and timing channels. CTR of 102.03 ± 1.9 ps full-width-at-half-maximum (FWHM) was achieved using single 3×3×10 mm³ "fast- LGSO" crystal elements, wrapped in Teflon tape and side coupled to a linear array of 3 SiPMs. In addition, the measured average CTR was 113.4 ± 0.7 ps for the side- coupled 2×4 crystal array. The readout architecture presented in this work is designed to be scalable to large area module detectors with a goal to create the first TOF-PET system with 100 ps FWHM CTR.
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http://dx.doi.org/10.1088/1361-6560/abf1bcDOI Listing
March 2021

Biomedical engineering letters' decade-long success.

Authors:
Jae Sung Lee

Biomed Eng Lett 2021 Feb 3;11(1):1-2. Epub 2021 Feb 3.

Department of Nuclear Medicine, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080 Korea.

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http://dx.doi.org/10.1007/s13534-021-00183-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7930167PMC
February 2021

Clinical comparison of the over-the-top and flexor carpi ulnaris split approaches for the treatment of anteromedial facet fractures of the coronoid process.

J Shoulder Elbow Surg 2021 Mar 3. Epub 2021 Mar 3.

Department of Orthropaedic Surgery, Hospital of Chung-Ang University of Medicine, Seoul, Republic of Korea. Electronic address:

Background: The flexor carpi ulnaris (FCU)-split approach and the over-the-top approach have been used frequently for the fixation of anteromedial facet (AMF) fractures of the coronoid process. Clinical studies have not compared functional recovery and complication rates associated with these approaches. This study aimed to compare the clinical effectiveness of the over-the-top and FCU-split approaches for the treatment of AMF fractures of the coronoid process.

Methods: Thirty-two patients who underwent surgery for AMF fractures between January 2013 and August 2019 were divided into the FCU-split and over-the-top groups. The FCU-split approach was used from January 2013 to March 2016, and the over-the-top approach was used from April 2016 to August 2019. Bony union, radiographic signs of osteoarthritis (Broberg and Morrey classification), and development of heterotopic ossification were evaluated. Postoperative pain score (visual analog scale at 2 days after the operation), surgical time (minutes), range of motion of the elbow, elbow function (Mayo Elbow Performance Score [MEPS]), and the presence of postoperative ulnar neuropathy were also compared between the two groups.

Results: The FCU-split and over-the-top approaches were performed in 15 and 17 patients, respectively. The mean age was 46 ± 13 years (range, 22-67 years), and the mean follow-up duration was 19± 6.7 months (range, 13-38 months). All coronoid fractures had a solid osseous union during the follow-up, and no subluxation or dislocation was observed in the two groups. The occurrence of heterotopic ossification and the grade of posttraumatic arthritis did not differ significantly between the groups (all p >0.05). There were also no significant differences between the groups in terms of postoperative pain score, range of motion, and MEPS (all p >0.05). However, the surgical time was shorter for the over-the-top approach than that for the FCU-split approach (79± 23 versus 101 ± 14, p = 0.008), and the surgical time was significantly associated with the fracture classification and surgical approach (p = 0.001 and 0.003, respectively). In addition, postoperative ulnar neuropathy occurred less with the over-the-top approach than with the FCU-spilt approach (5.9% versus 46%, p = 0.013).

Conclusion: Both the FCU-split and over-the-top approaches were appropriate for performing the buttress plate fixation for AMF fractures of the coronoid process and for restoring the elbow stability. The fixation of AMF fractures through the over-the-top approach was technically easier and had less incidence of postoperative ulnar neuropathy.
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http://dx.doi.org/10.1016/j.jse.2021.01.035DOI Listing
March 2021

Development and Initial Results of a Brain PET Insert for Simultaneous 7-Tesla PET/MRI Using an FPGA-Only Signal Digitization Method.

IEEE Trans Med Imaging 2021 Feb 24;PP. Epub 2021 Feb 24.

In this study, we developed a positron emission tomography (PET) insert for simultaneous brain imaging within 7-Tesla (7T) magnetic resonance (MR) imaging scanners. The PET insert has 18 sectors, and each sector is assembled with two-layer depth-of-interaction (DOI)-capable high-resolution block detectors. The PET scanner features a 16.7-cm-long axial field-of-view (FOV) to provide entire human brain images without bed movement. The PET scanner early digitizes a large number of block detector signals at a front-end data acquisition (DAQ) board using a novel field-programmable gate array (FPGA)-only signal digitization method. All the digitized PET data from the front-end DAQ boards are transferred using gigabit transceivers via non-magnetic high-definition multimedia interface (HDMI) cables. A back-end DAQ system provides a common clock and synchronization signal for FPGAs over the HDMI cables. An active cooling system using copper heat pipes is applied for thermal regulation. All the 2.17-mm-pitch crystals with two-layer DOI information were clearly identified in the block detectors, exhibiting a system-level energy resolution of 12.6%. The PET scanner yielded clear hot-rod and Hoffman brain phantom images and demonstrated 3D PET imaging capability without bed movement. We also performed a pilot simultaneous PET/MR imaging study of a brain phantom. The PET scanner achieved a spatial resolution of 2.5 mm at the center FOV (NU 4) and a sensitivity of 18.9 kcps/MBq (NU 2) and 6.19% (NU 4) in accordance with the National Electrical Manufacturers Association (NEMA) standards.
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http://dx.doi.org/10.1109/TMI.2021.3062066DOI Listing
February 2021

Translating amyloid PET of different radiotracers by a deep generative model for interchangeability.

Neuroimage 2021 May 19;232:117890. Epub 2021 Feb 19.

Department of Nuclear Medicine, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Republic of Korea. Electronic address:

It is challenging to compare amyloid PET images obtained with different radiotracers. Here, we introduce a new approach to improve the interchangeability of amyloid PET acquired with different radiotracers through image-level translation. Deep generative networks were developed using unpaired PET datasets, consisting of 203 [C]PIB and 850 [F]florbetapir brain PET images. Using 15 paired PET datasets, the standardized uptake value ratio (SUVR) values obtained from pseudo-PIB or pseudo-florbetapir PET images translated using the generative networks was compared to those obtained from the original images. The generated amyloid PET images showed similar distribution patterns with original amyloid PET of different radiotracers. The SUVR obtained from the original [F]florbetapir PET was lower than those obtained from the original [C]PIB PET. The translated amyloid PET images reduced the difference in SUVR. The SUVR obtained from the pseudo-PIB PET images generated from [F]florbetapir PET showed a good agreement with those of the original PIB PET (ICC = 0.87 for global SUVR). The SUVR obtained from the pseudo-florbetapir PET also showed a good agreement with those of the original [F]florbetapir PET (ICC = 0.85 for global SUVR). The ICC values between the original and generated PET images were higher than those between original [C]PIB and [F]florbetapir images (ICC = 0.65 for global SUVR). Our approach provides the image-level translation of amyloid PET images obtained using different radiotracers. It may facilitate the clinical studies designed with variable amyloid PET images due to long-term clinical follow-up as well as multicenter trials by enabling the translation of different types of amyloid PET.
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http://dx.doi.org/10.1016/j.neuroimage.2021.117890DOI Listing
May 2021

Abnormal neuroinflammation in fibromyalgia and CRPS using [11C]-(R)-PK11195 PET.

PLoS One 2021 8;16(2):e0246152. Epub 2021 Feb 8.

Emotional Information and Communication Technology Association, Seoul, Republic of Korea.

Purpose: Fibromyalgia (FM) and complex regional pain syndrome (CRPS) share many pathological mechanisms related to chronic pain and neuroinflammation, which may contribute to the multifactorial pathological mechanisms in both FM and CRPS. The aim of this study was to assess neuroinflammation in FM patients compared with that in patients with CRPS and healthy controls.

Methods: Neuroinflammation was measured as the distribution volume ratio (DVR) of [11C]-(R)-PK11195 positron emission tomography (PET) in 12 FM patients, 11 patients with CRPS and 15 healthy controls.

Results: Neuroinflammation in FM patients was significantly higher in the left pre (primary motor cortex) and post (primary somatosensory cortex) central gyri (p < 0.001), right postcentral gyrus (p < 0.005), left superior parietal and superior frontal gyri (p < 0.005), left precuneus (p < 0.01), and left medial frontal gyrus (p = 0.036) compared with healthy controls. Furthermore, the DVR of [11C]-(R)-PK11195 in FM patients demonstrated decreased neuroinflammation in the medulla (p < 0.005), left superior temporal gyrus (p < 0.005), and left amygdala (p = 0.020) compared with healthy controls.

Conclusions: To the authors' knowledge, this report is the first to describe abnormal neuroinflammation levels in the brains of FM patients compared with that in patients with CRPS using [11C]-(R)-PK11195 PET. The results suggested that abnormal neuroinflammation can be an important pathological factor in FM. In addition, the identification of common and different critical regions related to abnormal neuroinflammation in FM, compared with patients with CRPS and healthy controls, may contribute to improved diagnosis and the development of effective medical treatment for patients with FM.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0246152PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7870009PMC
February 2021

The effect of single-nucleotide polymorphisms within heat shock protein beta 1 on beef quantity in Korean native steers.

Arch Anim Breed 2020 17;63(2):417-422. Epub 2020 Nov 17.

Department of Animal Science and Technology, Sanghuh College of Life Sciences, Konkuk University, Seoul, 05029, Republic of Korea.

Heat shock protein beta 1 (), a member of the heat-shock family of protein, is a relatively small (27 kDa) molecular chaperone protein associated with cellular development. The relationship between expression and muscle growth in beef cattle has previously been reported, but there have been no reports of DNA markers related to meat quantity in Korean native steers. Therefore, the aim of this study was to evaluate the relationship of single-nucleotide polymorphisms (SNPs) within in terms of the carcass traits related to muscle growth in Korean native steers. Through direct sequencing, we discovered three SNPs: g.111 T > C SNP (rs208395876) and g.2548 C > G SNP (rs483014585) were respectively located in 5  UTR (untranslated region) and 3  UTR. Further, g.2352 T > C SNP (rs110832311) was located in the adjacent region of the RNA splicing site. The least square means of steers with a CC genotype of g.111 T > C SNP had a significantly higher meat ratio (    0.04), while the least square means of steers with a CC genotype of g.2352 T > C SNP had a significantly higher meat ratio (    0.002) and lower back-fat thickness (    0.004) than those of the other genotype. Moreover, although the least square means of steers with CC-CC, CT-CC, and TT-CC genotypes were significantly decreased for back-fat thickness, they were significantly increased for the meat ratio. Therefore, our results suggested that g.111 T > C SNP and g.2352 T > C SNP could be a causal mutation related to an adipose metabolism in Korean cattle steer.
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http://dx.doi.org/10.5194/aab-63-417-2020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7810230PMC
November 2020

Deep learning-Based 3D inpainting of brain MR images.

Sci Rep 2021 Jan 18;11(1):1673. Epub 2021 Jan 18.

Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea.

The detailed anatomical information of the brain provided by 3D magnetic resonance imaging (MRI) enables various neuroscience research. However, due to the long scan time for 3D MR images, 2D images are mainly obtained in clinical environments. The purpose of this study is to generate 3D images from a sparsely sampled 2D images using an inpainting deep neural network that has a U-net-like structure and DenseNet sub-blocks. To train the network, not only fidelity loss but also perceptual loss based on the VGG network were considered. Various methods were used to assess the overall similarity between the inpainted and original 3D data. In addition, morphological analyzes were performed to investigate whether the inpainted data produced local features similar to the original 3D data. The diagnostic ability using the inpainted data was also evaluated by investigating the pattern of morphological changes in disease groups. Brain anatomy details were efficiently recovered by the proposed neural network. In voxel-based analysis to assess gray matter volume and cortical thickness, differences between the inpainted data and the original 3D data were observed only in small clusters. The proposed method will be useful for utilizing advanced neuroimaging techniques with 2D MRI data.
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http://dx.doi.org/10.1038/s41598-020-80930-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7814079PMC
January 2021

Arthroscopic Transosseous Repair of Foveal Tears of the Triangular Fibrocartilage Complex: A Systematic Review of Clinical Outcomes.

Arthroscopy 2020 Dec 24. Epub 2020 Dec 24.

Department of Orthopaedic Surgery, Hospital of Chung-Ang University of Medicine, Seoul, Republic of Korea. Electronic address:

Purpose: To determine whether arthroscopic transosseous foveal repair of the triangular fibrocartilage complex (TFCC) results in significant and clinically relevant improvement in clinical outcomes including pain and function with low complication and reoperation rates.

Methods: We reviewed studies investigating the clinical outcomes of arthroscopic transosseous foveal repair of the TFCC through MEDLINE, Embase, and the Cochrane Library. Studies on TFCC repair performed with an open or capsular technique and combined with other procedures, such as ulnar shortening osteotomy and a wafer procedure, were excluded. Methodologic quality was assessed using the Methodological Index for Non-randomized Studies score. Clinical outcomes were assessed using range of motion, grip strength, and patient-reported outcomes. Clinically relevant improvement was determined using the minimal clinically important difference (MCID).

Results: A total of 443 unique studies were identified, of which 7 (131 patients) met the inclusion criteria. The mean age ranged from 27 to 37 years, and the mean follow-up period ranged from 23.5 to 31.1 months. The grip strength (as a percentage) increased after foveal repair of the TFCC in all studies (mean difference range, 11.8% to 22.3%). All studies also reported an improvement in the visual analog scale score (mean difference range, -9.8 to -1.88); Modified Mayo Wrist Score (mean difference range, 10.5 to 27); and Disabilities of the Arm, Shoulder and Hand score (mean difference range, -51.8 to -24.48). Considering clinically relevant improvements based on the MCID, 4 of 5 studies reporting the visual analog scale score showed improvements in this score (MCID, 2) and all studies reporting the Disabilities of the Arm, Shoulder and Hand score showed improvements in this score (MCID, 10). Most complications recovered without any treatment, and 3 patients (2.29%) needed a reoperation.

Conclusions: Arthroscopic transosseous foveal repair of the TFCC resulted in improvements in grip strength and functional outcomes with low complication and reoperation rates. However, the evidence for which technique produces better clinical outcomes remains limited.

Level Of Evidence: Level IV, systematic review of Level III and IV studies.
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http://dx.doi.org/10.1016/j.arthro.2020.12.209DOI Listing
December 2020

Negatively-Doped Single-Walled Carbon Nanotubes Decorated with Carbon Dots for Highly Selective NO Detection.

Nanomaterials (Basel) 2020 Dec 14;10(12). Epub 2020 Dec 14.

Sensor System Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.

In this study, we demonstrated a highly selective chemiresistive-type NO gas sensor using facilely prepared carbon dot (CD)-decorated single-walled carbon nanotubes (SWCNTs). The CD-decorated SWCNT suspension was characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), and UV-visible spectroscopy, and then spread onto an SiO/Si substrate by a simple and cost-effective spray-printing method. Interestingly, the resistance of our sensor increased upon exposure to NO gas, which was contrary to findings previously reported for SWCNT-based NO gas sensors. This is because SWCNTs are strongly doped by the electron-rich CDs to change the polarity from -type to -type. In addition, the CDs to SWCNTs ratio in the active suspension was critical in determining the response values of gas sensors; here, the 2:1 device showed the highest value of 42.0% in a sensing test using 4.5 ppm NO gas. Furthermore, the sensor selectively responded to NO gas (response ~15%), and to other gases very faintly (NO, response ~1%) or not at all (CO, CH, and CH). We propose a reasonable mechanism of the CD-decorated SWCNT-based sensor for NO sensing, and expect that our results can be combined with those of other researches to improve various device performances, as well as for NO sensor applications.
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http://dx.doi.org/10.3390/nano10122509DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7764981PMC
December 2020

Receptor mimicking TGF-β1 binding peptide for targeting TGF-β1 signaling.

Biomater Sci 2021 Feb;9(3):645-652

Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA. and Department of Orthopedics and Rehabilitation, University of Wisconsin-Madison, Madison, WI, USA and Materials Science Program, University of Wisconsin-Madison, Madison, WI, USA.

Prolonged and elevated transforming growth factor-β1 (TGF-β1) signaling can lead to undesired scar formation during tissue repair and fibrosis that is often a result of chronic inflammation in the lung, kidney, liver, heart, skin, and joints. We report new TGF-β1 binding peptides that interfere with TGF-β1 binding to its cognate receptors and thus attenuate its biological activity. We identified TGF-β1 binding peptides from the TGF-β1 binding domains of TGF-β receptors and engineered their sequences to facilitate chemical conjugation to biomaterials using molecular docking simulations. The in vitro binding studies and cell-based assays showed that RIPΔ, which was derived from TGF-β type I receptor, bound TGF-β1 in a sequence-specific manner and reduced the biological activity of TGF-β1 when the peptide was presented either in soluble form or conjugated to a commonly used synthetic biomaterial. This approach may have implications for clinical applications such as treatment of various fibrotic diseases and soft tissue repair and offer a design strategy for peptide antibodies based on the biomimicry of ligand-receptor interactions.
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http://dx.doi.org/10.1039/d0bm01374aDOI Listing
February 2021

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Nucl Med Mol Imaging 2020 Dec 20;54(6):299-304. Epub 2020 Oct 20.

Department of Nuclear Medicine, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul, 03080 South Korea.

Purpose: Early deep-learning-based image denoising techniques mainly focused on a fully supervised model that learns how to generate a clean image from the noisy input (noise2clean: N2C). The aim of this study is to explore the feasibility of the self-supervised methods (noise2noise: N2N and noiser2noise: Nr2N) for PET image denoising based on the measured PET data sets by comparing their performance with the conventional N2C model.

Methods: For training and evaluating the networks, F-FDG brain PET/CT scan data of 14 patients was retrospectively used (10 for training and 4 for testing). From the 60-min list-mode data, we generated a total of 100 data bins with 10-s duration. We also generated 40-s-long data by adding four non-overlapping 10-s bins and 300-s-long reference data by adding all list-mode data. We employed U-Net that is widely used for various tasks in biomedical imaging to train and test proposed denoising models.

Results: All the N2C, N2N, and Nr2N were effective for improving the noisy inputs. While N2N showed equivalent PSNR to the N2C in all the noise levels, Nr2N yielded higher SSIM than N2N. N2N yielded denoised images similar to reference image with Gaussian filtering regardless of input noise level. Image contrast was better in the N2N results.

Conclusion: The self-supervised denoising method will be useful for reducing the PET scan time or radiation dose.
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http://dx.doi.org/10.1007/s13139-020-00667-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7704825PMC
December 2020

Functional recovery after peripheral nerve injury via sustained growth factor delivery from mineral-coated microparticles.

Neural Regen Res 2021 May;16(5):871-877

Department of Neurological Surgery, University of Wisconsin, Madison, WI, USA.

The gold standard for treating peripheral nerve injuries that have large nerve gaps where the nerves cannot be directly sutured back together because it creates tension on the nerve, is to incorporate an autologous nerve graft. However, even with the incorporation of a nerve graft, generally patients only regain a small portion of function in limbs affected by the injury. Although, there has been some promising results using growth factors to induce more axon growth through the nerve graft, many of these previous therapies are limited in their ability to release growth factors in a sustained manner and tailor them to a desired time frame. The ideal drug delivery platform would deliver growth factors at therapeutic levels for enough time to grow axons the entire length of the nerve graft. We hypothesized that mineral coated microparticles (MCMs) would bind, stabilize and release biologically active glial cell-derived neurotrophic factor (GDNF) and nerve growth factor (NGF) in a sustained manner. Therefore, the objective of this study was to test the ability of MCMs releasing growth factors at the distal end of a 10 mm sciatic nerve graft, to induce axon growth through the nerve graft and restore hind limb function. After sciatic nerve grafting in Lewis rats, the hind limb function was tested weekly by measuring the angle of the ankle at toe lift-off while walking down a track. Twelve weeks after grafting, the grafts were harvested and myelinated axons were analyzed proximal to the graft, in the center of the graft, and distal to the graft. Under physiological conditions in vitro, the MCMs delivered a burst release of NGF and GDNF for 3 days followed by a sustained release for at least 22 days. In vivo, MCMs releasing NGF and GDNF at the distal end of sciatic nerve grafts resulted in significantly more myelinated axons extending distal to the graft when compared to rats that received nerve grafts without growth factor treatment. The rats with nerve grafts incorporated with MCMs releasing NGF and GDNF also showed significant improvement in hind limb function starting at 7 weeks postoperatively and continuing through 12 weeks postoperatively when compared to rats that received nerve grafts without growth factor treatment. In conclusion, MCMs released biologically active NGF and GDNF in a sustained manner, which significantly enhanced axon growth resulting in a significant improvement of hind limb function in rats. The animal experiments were approved by University of Wisconsin-Madison Animal Care and Use Committee (ACUC, protocol# M5958) on January 3, 2018.
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http://dx.doi.org/10.4103/1673-5374.297786DOI Listing
May 2021

In vivo gamma-aminobutyric acid-A/benzodiazepine receptor availability and genetic liability in asymptomatic individuals with high genetic loading of schizophrenia: A [11C]flumazenil positron emission tomography study.

Hum Psychopharmacol 2021 Mar 13;36(2):e2766. Epub 2020 Nov 13.

Department of Psychiatry, Seoul National University College of Medicine, Seoul, Republic of Korea.

Objectives: Whilst reduced signalling and gene expression related to gamma-aminobutyric acid (GABA) play a role in the presumed pathophysiology of schizophrenia, its origin is unclear. Studying asymptomatic individuals with high genetic liability to schizophrenia (AIs) would provide insights. Therefore, this study aimed to investigate the role of genetic liability in GABAergic dysfunction of schizophrenia by exploring in vivo GABA-A/benzodiazepine receptor (GABAR) availability in AIs.

Methods: A total of 10 AIs with multiple relatives diagnosed as schizophrenia and 11 healthy controls underwent [11C]flumazenil positron emission tomography and neurocognitive function tests.

Results: There was no significant difference in [11C]flumazenil availability based on the groups. GABAR availability in caudate nuclei had positive correlations with genetic liability of AIs. GABAR availability in caudate nuclei and verbal memory measures of AIs revealed positive correlations. Only the correlation between right caudate and short-term verbal memory survived multiple-comparison correction (p = 0.030).

Conclusions: This study, for the first time, reports correlations between the genetic liability of schizophrenia and GABAR availability. Correlations between [11C]flumazenil binding in caudate of individuals with high genetic liability to schizophrenia suggests that the GABAergic dysfunction may arise from shared genetic factors and also that it may be responsible for cognitive impairment of AIs.
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http://dx.doi.org/10.1002/hup.2766DOI Listing
March 2021

Rediscovery of Seven Long-Forgotten Species of and (Oomycota).

Mycobiology 2020 Aug 12;48(5):331-340. Epub 2020 Aug 12.

Department of Biology, Kunsan National University, Gunsan, Korea.

The family Peronosporaceae, an obligate biotrophic group of Oomycota, causes downy mildew disease on many cultivated and ornamental plants such as beet, cucumber, grape, onion, rose, spinach, and sunflower. To investigate the diversity of Peronosporaceae species in Korea, we performed morphological analysis for dried plant herbariums with downy mildew infections by two largest genera, and . As a result, it was confirmed that there are five species of and two species of , which have been so far unrecorded in Korea, as well as rarely known in the world; (ex ), (ex ), (ex ), (ex ), (ex cf. ), (ex ), and (ex ). In addition, their phylogenetic relationship was inferred by molecular sequence analysis of ITS, LSU rDNA, and mtDNA. By rediscovering the seven missing species and barcoding their DNA sequences, this study provides valuable insights into the diversity and evolutionary studies of downy mildew pathogens.
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http://dx.doi.org/10.1080/12298093.2020.1798863DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7580582PMC
August 2020

"Dietary supplementation of L-tryptophan" increases muscle development, adipose tissue catabolism and fatty acid transportation in the muscles of Hanwoo steers.

J Anim Sci Technol 2020 Sep 30;62(5):595-604. Epub 2020 Sep 30.

Department of Animal Science and Technology, Sanghuh College of Life Sciences, Konkuk University, Seoul 05029, Korea.

This study investigated the effects of dietary rumen-protected L-tryptophan (TRP) supplementation (43.4 mg of L-tryptophan kg body weigt [BW]) for 65 days in Hanwoo steers on muscle development related to gene expressions and adipose tissue catabolism and fatty acid transportation in muscles. Eight Hanwoo steers (initial BW = 424.6 kg [SD 42.3]; 477 days old [SD 4.8]) were randomly allocated to two groups (n = 4) of control and treatment and were supplied with total mixed ration (TMR). The treatment group was fed with 15 g of rumen-protected TRP (0.1% of TMR as-fed basis equal to 43.4 mg of TRP kg BW) once a day at 0800 h as top-dressed to TMR. Blood samples were collected 3 times, at 0, 5, and 10 weeks of the experiment, for assessment of hematological and biochemical parameters. For gene study, the muscle samples (12 to 13 ribs, approximately 2 g) were collected from each individual by biopsy at end of the study (10 weeks). Growth performance parameters including final BW, average daily gain, and gain to feed ratio, were not different ( > 0.05) between the two groups. Hematological parameters including granulocyte, lymphocyte, monocyte, platelet, red blood cell, hematocrit, and white blood cell showed no difference ( > 0.05) between the two groups except for hemoglobin ( = 0.025), which was higher in the treatment than in the control group. Serum biochemical parameters including total protein, albumin, globulin, blood urea nitrogen, creatinine phosphokinase, glucose, nonesterified fatty acids, and triglyceride also showed no differences between the two groups ( > 0.05). Gene expression related to muscle development (Myogenic factor 6 [], myogenine []), adipose tissue catabolism (lipoprotein lipase []), and fatty acid transformation indicator (fatty acid binding protein 4 []) were increased in the treatment group compared to the control group ( < 0.05). Collectively, supplementation of TRP (65 days in this study) promotes muscle development and increases the ability of the animals to catabolize and transport fat in muscles due to an increase in expressions of , , , and gene.
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http://dx.doi.org/10.5187/jast.2020.62.5.595DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7553846PMC
September 2020

Brownian heat engine with active reservoirs.

Phys Rev E 2020 Sep;102(3-1):032116

School of Physics and Quantum Universe Center, Korea Institute for Advanced Study, Seoul 02455, Korea.

Microorganisms such as bacteria are active matter which consume chemical energy and generate their unique run-and-tumble motion. A swarm of such microorganisms provide a nonequilibrium active environment whose noise characteristics are different from those of thermal equilibrium reservoirs. One important difference is a finite persistence time, which is considerably large compared to that of the equilibrium noise, that is, the active noise is colored. Here we study a mesoscopic energy-harvesting device (engine) with active reservoirs harnessing this noise nature. For an exactly solvable linear model, we show that the performance from the active environment can surpass that from the equilibrium environment. Furthermore, we propose a proper definition of the active-reservoir temperature and show that the engine efficiency can overcome the conventional Carnot bound, thus the power-efficiency trade-off constraint is released. We also show that the efficiency at the maximum power can surpass the Curzon-Ahlborn efficiency. This remarkable enhancement originates from the extra unconventional entropy production beyond the conventional Clausius entropy production, due to the non-Markovian nature of the active reservoirs. Interestingly, the supremacy of the active engine critically depends on the timescale symmetry of two active reservoirs.
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http://dx.doi.org/10.1103/PhysRevE.102.032116DOI Listing
September 2020

The Statistical Structure of the Hippocampal Code for Space as a Function of Time, Context, and Value.

Cell 2020 Oct 8;183(3):620-635.e22. Epub 2020 Oct 8.

HHMI Janelia Research Campus, Ashburn, VA, USA. Electronic address:

Hippocampal activity represents many behaviorally important variables, including context, an animal's location within a given environmental context, time, and reward. Using longitudinal calcium imaging in mice, multiple large virtual environments, and differing reward contingencies, we derived a unified probabilistic model of CA1 representations centered on a single feature-the field propensity. Each cell's propensity governs how many place fields it has per unit space, predicts its reward-related activity, and is preserved across distinct environments and over months. Propensity is broadly distributed-with many low, and some very high, propensity cells-and thus strongly shapes hippocampal representations. This results in a range of spatial codes, from sparse to dense. Propensity varied ∼10-fold between adjacent cells in salt-and-pepper fashion, indicating substantial functional differences within a presumed cell type. Intracellular recordings linked propensity to cell excitability. The stability of each cell's propensity across conditions suggests this fundamental property has anatomical, transcriptional, and/or developmental origins.
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http://dx.doi.org/10.1016/j.cell.2020.09.024DOI Listing
October 2020

Eponychial flap elevation method for surgical excision of a subungual glomus tumor.

Dermatol Ther 2020 11 7;33(6):e14330. Epub 2020 Oct 7.

Department of Orthopedic Surgery, Chung-Ang University Hospital, Seoul, South Korea.

The clinical symptoms of glomus tumors are pain, tenderness, nail discoloration, and cold intolerance. The only treatment for subungual glomus tumors is surgical removal. In this clinical study, we present an eponychium preserving method as a new innovative surgical approach for subungual glomus tumor. We retrospectively reviewed the data of 27 patients with subungual glomus tumors who underwent tumor resection using the eponychial flap elevation method between March 2010 and 2019. After the excision of the subungual glomus tumor using the eponychial flap elevation method, wound problems, severe pain, and nail deformity other than a minimal scar were not noted. The innovative eponychial flap elevation method is a simple and straightforward method for the management of subungual glomus tumors; the tumors can be sufficiently exposed and completely excised using this method while avoiding secondary nail dystrophy. This method can be another option among several methods of subungual glomus tumor removal.
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http://dx.doi.org/10.1111/dth.14330DOI Listing
November 2020

Variation in Seed Metabolites between Two Indica Rice Accessions Differing in Seed Longevity.

Plants (Basel) 2020 Sep 19;9(9). Epub 2020 Sep 19.

T.T. Chang Genetic Resources Center, Strategic Innovation Platform, International Rice Research Institute, Los Baños, College, Laguna 4031, Philippines.

For a better understanding of germination after seed storage, metabolite profiling was conducted using hybrid triple quadrupole time-of-flight (QTOF) mass spectrometry. After moisture content (MC) equilibration, seeds of "WAS170" (short-lived) and "IR65483" (long-lived) were stored at 10.9% MC and 45 °C. Samples for metabolite analysis were taken after 0 and 20 days of storage. Among 288 metabolites, two flavonoids (kaempferide and quercetin-3-arabinoside), one amino acid (S-sulfocysteine) and one sugar (D-glucose) increased in "IR65483" seeds after storage but were not detected in "WAS170" seeds. Based on the genome sequence database, we identified clear allelic differences with non-synonymous mutations on the six flavonol synthase genes regulating the accumulation of kaempferol- and quercetin-metabolites. On the other hand, two metabolites (thiamine monophosphate and harmaline) increased in short-lived seeds after storage; these metabolites could be potential biochemical indicators of seed deterioration.
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http://dx.doi.org/10.3390/plants9091237DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7569829PMC
September 2020

Gradient tantalum-doped hematite homojunction photoanode improves both photocurrents and turn-on voltage for solar water splitting.

Nat Commun 2020 Sep 15;11(1):4622. Epub 2020 Sep 15.

School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, 44919, Republic of Korea.

Hematite has a great potential as a photoanode for photoelectrochemical (PEC) water splitting by converting solar energy into hydrogen fuels, but the solar-to-hydrogen conversion efficiency of state-of-the-art hematite photoelectrodes are still far below the values required for practical hydrogen production. Here, we report a core-shell formation of gradient tantalum-doped hematite homojunction nanorods by combination of hydrothermal regrowth strategy and hybrid microwave annealing, which enhances the photocurrent density and reduces the turn-on voltage simultaneously. The unusual bi-functional effects originate from the passivation of the surface states and intrinsic built-in electric field by the homojunction formation. The additional driving force provided by the field can effectively suppress charge-carrier recombination both in the bulk and on the surface of hematite, especially at lower potentials. Moreover, the synthesized homojunction shows a remarkable synergy with NiFe(OH) cocatalyst with significant additional improvements of photocurrent density and cathodic shift of turn-on voltage. The work has nicely demonstrated multiple collaborative strategies of gradient doping, homojunction formation, and cocatalyst modification, and the concept could shed light on designing and constructing the efficient nanostructures of semiconductor photoelectrodes in the field of solar energy conversion.
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http://dx.doi.org/10.1038/s41467-020-18484-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7493915PMC
September 2020

In Vitro and In Vivo Studies of Rumen-Protected Microencapsulated Supplement Comprising Linseed Oil, Vitamin E, Rosemary Extract, and Hydrogenated Palm Oil on Rumen Fermentation, Physiological Profile, Milk Yield, and Milk Composition in Dairy Cows.

Animals (Basel) 2020 Sep 11;10(9). Epub 2020 Sep 11.

Department of Animal Science and Technology, Konkuk University, Seoul 05029, Korea.

The aim of the present study was to evaluate the effects of adding dietary rumen-protected microencapsulated supplements into the ruminal fluid on the milk fat compositions of dairy cows. These supplements comprised linseed oil, vitamin E, rosemary extract, and hydrogenated palm oil (MO; Microtinic Omega, Vetagro S.p.A, Reggio Emilia, Italy). For in vitro ruminal fermentation, Holstein-Friesian dairy cows each equipped with a rumen cannula were used to collect ruminal fluid. Different amounts (0%, 1%, 2%, 3%, 4%, and 5%) of MO were added to the diets to collect ruminal fluids. For the in vivo study, 36 Holstein-Friesian dairy cows grouped by milk yield (32.1 ± 6.05 kg/d/head), days in milk (124 ± 84 d), and parity (2 ± 1.35) were randomly and evenly assigned to 0.7% linseed oil (LO; as dry matter (DM) basis) and 2% MO (as DM basis) groups. These two groups were fed only a basal diet (total mixed ration (TMR), silage, and concentrate for 4 weeks) (period 1). They were then fed with the basal diet supplemented with oil (0.7 LO and 2% MO of DM) for 4 weeks (period 2). In the in vitro experiment, the total gas production was found to be numerically decreased in the group supplemented with 3% MO at 48 h post in vitro fermentation. A reduction of total gas production (at 48 h) and increase in ammonia concentration (24 h) were also observed in the group supplemented with 4% to 5% MO ( < 0.05). There were no differences in the in vitro fermentation results, including pH, volatile fatty acids, or CH among groups supplemented with 0%, 1%, and 2% MO. The results of the in vitro study suggest that 2% MO is an optimal dosage of MO supplementation in cows' diets. In the in vivo experiment, the MO supplement more significantly ( < 0.01) increased the yield of total w3 fatty acids than LO (9.24 vs. 17.77 mg/100 g milk). As a result, the ratio of total omega-6 to omega-3 fatty acids was decreased ( < 0.001) in the MO group compared to that in the LO group (6.99 vs. 3.48). However, the milk yield and other milk compositions, except for milk urea nitrogen, were similar between the two groups ( > 0.05). Collectively, these results suggest that the dietary supplementation of 2% MO is beneficial for increasing omega-3 fatty acids without any negative effects on the milk yield of dairy cows.
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http://dx.doi.org/10.3390/ani10091631DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7552145PMC
September 2020

Dopamine dysregulation in psychotic relapse after antipsychotic discontinuation: an [F]DOPA and [C]raclopride PET study in first-episode psychosis.

Mol Psychiatry 2020 Sep 14. Epub 2020 Sep 14.

Department of Psychiatry, Seoul National University Bundang Hospital, Gyeonggi-do, Republic of Korea.

Although antipsychotic drugs are effective for relieving the psychotic symptoms of first-episode psychosis (FEP), psychotic relapse is common during the course of the illness. While some FEPs remain remitted even without medication, antipsychotic discontinuation is regarded as the most common risk factor for the relapse. Considering the actions of antipsychotic drugs on presynaptic and postsynaptic dopamine dysregulation, this study evaluated possible mechanisms underlying relapse after antipsychotic discontinuation. Twenty five FEPs who were clinically stable and 14 matched healthy controls were enrolled. Striatal dopamine activity was assessed as K value using [F]DOPA PET before and 6 weeks after antipsychotic discontinuation. The D2/3 receptor availability was measured as BP using [C]raclopride PET after antipsychotic discontinuation. Healthy controls also underwent PET scans according to the corresponding schedule of the patients. Patients were monitored for psychotic relapse during 12 weeks after antipsychotic discontinuation. 40% of the patients showed psychotic relapse after antipsychotic discontinuation. The change in K value over time significantly differed between relapsed, non-relapsed patients and healthy controls (Week*Group: F = 4.827, df = 2,253.193, p = 0.009). In relapsed patients, a significant correlation was found between baseline striatal K values and time to relapse after antipsychotic discontinuation (R = 0.518, p = 0.018). BP were not significantly different between relapsed, non-relapsed patients and healthy controls (F = 1.402, df = 2,32.000, p = 0.261). These results suggest that dysfunctional dopamine autoregulation might precipitate psychotic relapse after antipsychotic discontinuation in FEP. This finding could be used for developing a strategy for the prevention of psychotic relapse related to antipsychotic discontinuation.
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http://dx.doi.org/10.1038/s41380-020-00879-0DOI Listing
September 2020

Testosterone deficiency caused by castration increases adiposity in male rats in a tissue-specific and diet-dependent manner.

Genes Nutr 2020 Aug 17;15(1):14. Epub 2020 Aug 17.

National Institute of Animal Science, Rural Development Administration, Wanju-gun, Jeollabuk-do, 55365, Republic of Korea.

Background: Testosterone deficiency in men is clinically associated with the development of metabolic syndrome, which manifests as obesity, hepatic steatosis, and type-2 diabetes. We investigated the effects of castration-induced testosterone deficiency on body adiposity and the expression of genes related to lipid metabolism and glucose uptake and androgen signaling in male rats fed a normal diet (ND) or a high-fat diet (HFD).

Methods: Changes in lipid and glucose metabolism and androgen signaling were investigated at physiological and molecular levels in the muscle, liver, and adipose tissues of non-castrated and castrated rats under ND or HFD feeding.

Results: Castration-induced testosterone deficiency predisposed animals on ND to early development of fatty liver by activating fatty acid (FA) synthesis, whereas HFD activated hepatic FA uptake CD36 expression, leading to the development of hepatic steatosis. In rats fed ND, castration induced muscle fat accumulation by activating CD36 expression. In the subcutaneous fat of ND-fed rats, castration increased adiposity and the expression of FA synthesis-related genes, but it decreased glucose transporter gene expression. In the abdominal fat of rats fed ND, castration increased adiposity by upregulating FA synthesis-related genes, and HFD promoted adiposity by inducing FA uptake, glucose transporter, and FA synthesis-related gene expression. In rats fed ND, castration decreased body growth and muscle weight and downregulated the expression of genes androgen signaling in the longissimus dorsi muscle.

Conclusions: Testosterone deficiency increases adiposity in a tissue-specific and diet-dependent manner. Testosterone deficiency decreases body and muscle weights and downregulates androgen signaling.
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http://dx.doi.org/10.1186/s12263-020-00673-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7433145PMC
August 2020

Air-stable and ultrasensitive solution-cast SWIR photodetectors utilizing modified core/shell colloidal quantum dots.

Nano Converg 2020 Aug 17;7(1):28. Epub 2020 Aug 17.

School of Electronics Engineering, College of IT Engineering, Kyungpook National University, 1370 Sankyuk-dong, Daegu, 702-701, Republic of Korea.

InGaAs-based photodetectors have been generally used for detection in the short-wave infrared (SWIR) region. However, the epitaxial process used to grow these materials is expensive; therefore, InGaAs-based photodetectors are limited to space exploration and military applications. Many researchers have expended considerable efforts to address the problem of SWIR photodetector development using lead sulfide (PbS) quantum dots (QDs). Along with their cost-efficient solution processability and flexible substrate compatibility, PbS QDs are highly interesting for the quantum-size-effect tunability of their bandgaps, spectral sensitivities, and wide absorption ranges. However, the performance of PbS QD-based SWIR photodetectors is limited owing to inefficient carrier transfer and low photo and thermal stabilities. In this study, a simple method is proposed to overcome these problems by incorporating CdS in PbS QD shells to provide efficient carrier transfer and enhance the long-term stability of SWIR photodetectors against oxidation. The SWIR photodetectors fabricated using thick-shell PbS/CdS QDs exhibited a high on/off (light/dark) ratio of 11.25 and a high detectivity of 4.0 × 10 Jones, which represents a greater than 10 times improvement in these properties relative to those of PbS QDs. Moreover, the lifetimes of thick-shell PbS/CdS QD-based SWIR photodetectors were significantly improved owing to the self-passivation of QD surfaces.
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http://dx.doi.org/10.1186/s40580-020-00238-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7429620PMC
August 2020