256 research outputs found
The thermal SZ tomography
The thermal Sunyaev-Zel'dovich (tSZ) effect directly measures the thermal
pressure of free electrons integrated along the line of sight and thus contains
valuable information on the thermal history of the universe. However, the
redshift information is entangled in the projection along the line of sight.
This projection effect severely degrades the power of the tSZ effect to
reconstruct the thermal history. We investigate the tSZ tomography technique to
recover this otherwise lost redshift information by cross correlating the tSZ
effect with galaxies of known redshifts, or alternatively with matter
distribution reconstructed from weak lensing tomography. We investigate in
detail the 3D distribution of the gas thermal pressure and its relation with
the matter distribution, through our adiabatic hydrodynamic simulation and the
one with additional gastrophysics including radiative cooling, star formation
and supernova feedback. (1) We find a strong correlation between the gas
pressure and matter distribution, with a typical cross correlation coefficient
r ~ 0.7 at k . 3h/Mpc and z < 2. This tight correlation will enable robust
cross correlation measurement between SZ surveys such as Planck, ACT and SPT
and lensing surveys such as DES and LSST, at ~20-100{\sigma} level. (2) We
propose a tomography technique to convert the measured cross correlation into
the contribution from gas in each redshift bin to the tSZ power spectrum.
Uncertainties in gastrophysics may affect the reconstruction at ~ 2% level, due
to the ~ 1% impact of gastrophysics on r, found in our simulations. However, we
find that the same gastrophysics affects the tSZ power spectrum at ~ 40% level,
so it is robust to infer the gastrophysics from the reconstructed redshift
resolved contribution.Comment: 10 pages, 7 figures, 2 appendices, accepted by Ap
Real-Time Simulated Avatar from Head-Mounted Sensors
We present SimXR, a method for controlling a simulated avatar from
information (headset pose and cameras) obtained from AR / VR headsets. Due to
the challenging viewpoint of head-mounted cameras, the human body is often
clipped out of view, making traditional image-based egocentric pose estimation
challenging. On the other hand, headset poses provide valuable information
about overall body motion, but lack fine-grained details about the hands and
feet. To synergize headset poses with cameras, we control a humanoid to track
headset movement while analyzing input images to decide body movement. When
body parts are seen, the movements of hands and feet will be guided by the
images; when unseen, the laws of physics guide the controller to generate
plausible motion. We design an end-to-end method that does not rely on any
intermediate representations and learns to directly map from images and headset
poses to humanoid control signals. To train our method, we also propose a
large-scale synthetic dataset created using camera configurations compatible
with a commercially available VR headset (Quest 2) and show promising results
on real-world captures. To demonstrate the applicability of our framework, we
also test it on an AR headset with a forward-facing camera.Comment: CVPR 2024 Hightlight. Website: https://www.zhengyiluo.com/SimXR
Continuous 3D Myocardial Motion Tracking via Echocardiography
Myocardial motion tracking stands as an essential clinical tool in the
prevention and detection of cardiovascular diseases (CVDs), the foremost cause
of death globally. However, current techniques suffer from incomplete and
inaccurate motion estimation of the myocardium in both spatial and temporal
dimensions, hindering the early identification of myocardial dysfunction. To
address these challenges, this paper introduces the Neural Cardiac Motion Field
(NeuralCMF). NeuralCMF leverages implicit neural representation (INR) to model
the 3D structure and the comprehensive 6D forward/backward motion of the heart.
This method surpasses pixel-wise limitations by offering the capability to
continuously query the precise shape and motion of the myocardium at any
specific point throughout the cardiac cycle, enhancing the detailed analysis of
cardiac dynamics beyond traditional speckle tracking. Notably, NeuralCMF
operates without the need for paired datasets, and its optimization is
self-supervised through the physics knowledge priors in both space and time
dimensions, ensuring compatibility with both 2D and 3D echocardiogram video
inputs. Experimental validations across three representative datasets support
the robustness and innovative nature of the NeuralCMF, marking significant
advantages over existing state-of-the-art methods in cardiac imaging and motion
tracking.Comment: 18 pages, 11 figure
Retroperitoneal laparoscopic partial nephrectomy for treatment of metanephric adenoma (Report of 6 cases)
OBJECTIVES: To investigate the clinical and pathological features of metanephric adenoma (MA) and the clinical outcome after retroperitoneal laparoscopic nephron-sparing surgery. METHODS: Six out of 183 partial nephrectomies performed during January 2009 to August 2014 were confirmed to be MA confirmed by postoperative pathological study. Perioperative parameters of the six patients were then retrospectively collected, analyzed and compared with current literature, including warm ischemia time (WIT), total operation time, estimated blood loss (EBL), positive surgical margin (PSM), and complications. Surgical and oncological outcome of all six patients were evaluated based on a mean follow up of 17 months (5–48 months). RESULTS: Tumors in all six cases were all successfully removed by partial nephrectomy. Mean WIT was 24.7 min (19–35 min). Mean operation time was 103.6 min (82–147 min). Mean EBL was 53.5 ml (20–85 ml). No conversion, transfusion or other major complication were observed in all six cases. Postoperative pathology confirmed negative surgical margin in all six cases. During a mean of 17 month follow up (5–48 months), no local recurrence or metastasis were found in all six cases. CONCLUSION: MA is a rare benign primary kidney epithelial cancer, which could hardly be differentiated from renal malignancies based on preoperative imaging. Our data suggested that retroperitoneal laparoscopic partial nephrectomy can be used for surgical treatment of MA, in terms of tumor control and preservation of renal function
Case report: A novel 10.8-kb deletion identified in the β-globin gene through the long-read sequencing technology in a Chinese family with abnormal hemoglobin testing results
BackgroundThalassemia is a common inherited hemoglobin disorder caused by a deficiency of one or more globin subunits. Substitution variants and deletions in the HBB gene are the major causes of β-thalassemia, of which large fragment deletions are rare and difficult to be detected by conventional polymerase chain reaction (PCR)-based methods.Case reportIn this study, we reported a 26-year-old Han Chinese man, whose routine blood parameters were found to be abnormal. Hemoglobin testing was performed on the proband and his family members, of whom only the proband's mother had normal parameters. The comprehensive analysis of thalassemia alleles (CATSA, a long-read sequencing-based approach) was performed to identify the causative variants. We finally found a novel 10.8-kb deletion including the β-globin (HBB) gene (Chr11:5216601-5227407, GRch38/hg38) of the proband and his father and brother, which were consistent with their hemoglobin testing results. The copy number and exact breakpoints of the deletion were confirmed by multiplex ligation-dependent probe amplification (MLPA) and gap-polymerase chain reaction (Gap-PCR) as well as Sanger sequencing, respectively.ConclusionWith this novel large deletion found in the HBB gene in China, we expand the genotype spectrum of β-thalassemia and show the advantages of long-read sequencing (LRS) for comprehensive and precise detection of thalassemia variants
Post-translational modifications are enriched within protein functional groups important to bacterial adaptation within a deep-sea hydrothermal vent environment
BACKGROUND: Post-translational modification (PTM) of proteins is one important strategy employed by bacteria for environmental adaptation. However, PTM profiles in deep-sea microbes remain largely unexplored. RESULTS: We provide here insight into PTMs in a hydrothermal vent microbial community through integration of metagenomics and metaproteomics. In total, 2919 unique proteins and 1306 unique PTMs were identified, whereas the latter included acetylation, deamination, hydroxylation, methylation, nitrosylation, oxidation, and phosphorylation. These modifications were unevenly distributed among microbial taxonomic and functional categories. A connection between modification types and particular functions was demonstrated. Interestingly, PTMs differed among the orthologous proteins derived from different bacterial groups. Furthermore, proteomic mapping to the draft genome of a Nitrospirae bacterium revealed novel modifications for proteins that participate in energy metabolism, signal transduction, and inorganic ion transport. CONCLUSIONS: Our results suggest that PTMs are enriched in specific functions, which would be important for microbial adaptation to extreme conditions of the hydrothermal vent. PTMs in deep-sea are highly diverse and divergent, and much broader investigations are needed to obtain a better understanding of their functional roles. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40168-016-0194-x) contains supplementary material, which is available to authorized users
Dynamic control and quantification of active sites on ceria for CO activation and hydrogenation
Ceria (CeO) is a widely used oxide catalyst, yet the nature of its active sites remains elusive. This study combines model and powder catalyst studies to elucidate the structure-activity relationships in ceria-catalyzed CO activation and hydrogenation. Well-defined ceria clusters are synthesized on planar CeO(111) and exhibit dynamic and tunable ranges of Ce coordination numbers, which enhance their interaction with CO. Reduced ceria clusters (e.g., CeO) bind CO strongly and facilitate its dissociation, while near-stoichiometric clusters (e.g., CeO) adsorb CO weakly and promote oxidation via carbonate formation. Unlike planar ceria surfaces, supported ceria clusters exhibit dynamic properties and enhanced catalytic activity, that mimic those of powder ceria catalysts. Insight from model studies provide a method to quantify active sites on powder ceria and guide further optimization of ceria catalysts for syngas conversion. This work marks a leap toward model-guided catalyst design and highlights the importance of site-specific catalysis
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