Machine Eye for Defects: Machine Learning-Based Solution to Identify and Characterize Topological Defects in Textured Images of Nematic Materials

Topological defects play a key role in the structures and dynamics of liquid crystals (LCs) and other ordered systems. There is a recent interest in studying defects in different biological systems with distinct textures. However, a robust method to directly recognize defects and extract their structural features from various traditional and nontraditional nematic systems remains challenging to date. Here we present a machine learning solution, termed Machine Eye for Defects (MED), for automated defect analysis in images with diverse nematic textures. MED seamlessly integrates state-of-the-art object detection networks, Segment Anything Model, and vision transformer algorithms with tailored computer vision techniques. We show that MED can accurately identify the positions, winding numbers, and orientations of $\pm 1/2$ defects across distinct cellular contours, sparse vector fields of nematic directors, actin filaments, microtubules, and simulation images of Gay--Berne particles. MED performs faster than conventional defect detection method and can achieve over 90\% accuracy on recognizing $\pm1/2$ defects and their orientations from vector fields and experimental tissue images. We further demonstrate that MED can identify defect types that are not included in the training data, such as giant-core defects and defects with higher winding number. Remarkably, MED can provide correct structural information about $\pm 1$ defects. As such, MED stands poised to transform studies of diverse ordered systems by providing automated, rapid, accurate, and insightful defect analysis

Experimental demonstrations of high-Q superconducting coplanar waveguide resonators

We designed and successfully fabricated an absorption-type of superconducting coplanar waveguide (CPW) resonators. The resonators are made from a Niobium film (about 160 nm thick) on a high-resistance Si substrate, and each resonator is fabricated as a meandered quarter-wavelength transmission line (one end shorts to the ground and another end is capacitively coupled to a through feedline). With a vector network analyzer we measured the transmissions of the applied microwave through the resonators at ultra-low temperature (e.g., at 20 mK), and found that their loaded quality factors are significantly high, i.e., up to 10^6. With the temperature increases slowly from the base temperature (i.e., 20 mK), we observed the resonance frequencies of the resonators are blue shifted and the quality factors are lowered slightly. In principle, this type of CPW-device can integrate a series of resonators with a common feedline, making it a promising candidate of either the data bus for coupling the distant solid-state qubits or the sensitive detector of single photons.Comment: Accepted by Chinese Science Bulleti

The Effect of Tong-Xie-Yao-Fang on Intestinal Mucosal Mast Cells in Postinfectious Irritable Bowel Syndrome Rats

Objective. To investigate the effects of Tong-Xie-Yao-Fang (TXYF) on intestinal mucosal mast cells in rats with postinfectious irritable bowel syndrome (PI-IBS). Design. PI-IBS rat models were established using a multistimulation paradigm. Then, rats were treated with TXYF intragastrically at doses of 2.5, 5.0, and 10.0 g·kg−1·d−1 for 14 days, respectively. Intestinal sensitivity was assessed based on abdominal withdrawal reflex (AWR) scores and fecal water content (FWC). Mast cell counts and the immunofluorescence of tryptase and c-Fos in intestinal mucosa were measured; and serum IL-1β, TNF-α, and histamine levels were determined. Results. AWR reactivity and FWC which were significantly increased could be observed in PI-IBS rats. Remarkably increased mast cell activation ratio in intestinal mucosa, together with increased serum TNF-α and histamine levels, could also be seen in PI-IBS rats; furthermore, PI-IBS-induced changes in mast cell activation and level of serum TNF-α and histamine could be reversed by TXYF treatment. Meanwhile, tryptase and c-Fos expression were also downregulated. Conclusion. TXYF improves PI-IBS symptoms by alleviating behavioral hyperalgesia and antidiarrhea, the underlying mechanism of which involves the inhibitory effects of TXYF on activating mucosal mast cells, downregulating tryptase and c-Fos expression, and reducing serum TNF-α and histamine levels

Genotypic spectrum of α-thalassemia and β-thalassemia in newborns of the Li minority in Hainan province, China

PurposeTo explore the genotypes and allele frequencies of α, β and α+β thalassemias in Li minorities, which resided in Hainan Province of China for a long time.MethodsIn the present study, 1,438 newborns of the Li minority were collected from January 2020 to April 2021. The genotypes of thalassemia were detected by fluorescence PCR and verified by flow-through hybridization PCR analyses. Rare genotypes were detected by restriction fragment length polymorphism electrophoresis and Sanger DNA sequencing.ResultsAmong 1,438 participants, 1,024 (71.2%) were diagnosed with any kind of thalassemia. Among all thalassemia carriers, 902 (88.09%) subjects were diagnosed with α-thalassemia, and 18 subtypes of α-thalassemia were detected, with the top three genotypes being −α4.2/αα (25.39%), −α3.7/αα (22.62%) and αWSα/αα (16.96%). Thirty-two (3.13%) patients were β-thalassemia carriers, and 6 types of β-thalassemia genotypes were detected. The top two genotypes were βCD41–42/βN (46.88%) and β−28/βN (18.75%). Additionally, 90 (8.79%) cases were α + β-thalassemia, and the top two genotypes were −α3.7/αα, βCD41–42/βN (30.00%) and −α4.2/αα, βCD41–42/βN (26.67%). Furthermore, two genotypes (−α4.2/HKαα and βCD76 GCT > CCT/βN) were first identified in Hainan Province, and βCD76 GCT > CCT/βN was first identified in China.ConclusionNewborns of Li have a higher prevalence of thalassemia for a long period, and further education on the impact of thalassemia, follow-up studies of the clinical manifestation and treatment and proper intervention methods should be designed to reduce the burden of thalassemia and enhance the quality of life in Li newborns

Cloning and characterization of a thermostable superoxide dismutase from the thermophilic bacterium Rhodothermus sp XMH10

A superoxide dismutase (SOD) gene was cloned from the thermophilic bacterium Rhodothermus sp. XMH10 for the first time and highly expressed in Escherichia coli. The Rhodothermus sp. XMH10 SOD (RhSOD) gene encodes 209 amino acids with a putative molecular weight of 23.6 kDa and a pI value of 5.53. The recombinant RhSOD was detected to be an iron type SOD and existed as a dimer on its natural status. Experiments revealed that this RhSOD showed high activity at 50-70 degrees C and pH 5.0. Compared to SODs from other thermophiles, it was highly thermostable, maintaining more than 90% of its activity after incubation at 70 degrees C for 12 h, only totally inactivated after more than 4-h incubation at 80 degrees C. It also showed much higher resistance to KCN, NaN3 and H2O2 as compared to other SODs