High-performance seawater oxidation by a homogeneous multimetallic layered double hydroxide electrocatalyst.

SignificanceSeawater is one of the most abundant resources on Earth. Direct electrolysis of seawater is a transformative technology for sustainable hydrogen production without causing freshwater scarcity. However, this technology is severely impeded by a lack of robust and active oxygen evolution reaction (OER) electrocatalysts. Here, we report a highly efficient OER electrocatalyst composed of multimetallic layered double hydroxides, which affords superior catalytic performance and long-term durability for high-performance seawater electrolysis. To the best of our knowledge, this catalyst is among the most active for OER and it advances the development of seawater electrolysis technology.

An intelligent intestinal bleeding diagnosis and treatment capsule system based on color recognition.

To our best knowledge, there are no non-invasive and painless means for the diagnosis and treatment of intestinal bleeding as of now, especially the segment of intestine that cannot be reached by endoscopy. We proposed an intelligent intestinal bleeding diagnosis and treatment capsule (IBDTC) system for the first time to diagnose and treat intestinal bleeding with low power consumption, estimated to be about 2.16mW. A hue-saturation-light (HSL) color space method was applied to diagnose bleeding according to H (hue) values of the film dyed by blood. A MEMS-based micro-igniter works as the critical component of the micro-thruster that houses the propellant (74.6% potassium nitrate, 11.9% sulfur, 13.5% charcoal) and the detonating agent (dinitrodiazophenol), to help release drug. Bleeding detection and ignition tests were performed to justify its feasibility and reliability. Results demonstrated that the bleeding diagnosis module of the IBDTC can effectively detect bleeding and the micro-igniter can successfully ignite the propellant. Owing to its simplicity and intelligence, the IBDTC system will pave a way for future accurate treatment of small intestinal bleeding with no injury, no pain, no complicated supporting equipment, no need for in vitro operation and positioning.

Interfacial Self-Assembly of Organized Ultrathin Films of Tripodal Metal-Terpyridyl Coordination Polymers as Luminophores and Heterogeneous Catalysts for Photocatalytic CO2 Reduction.

Metal-directed interfacial self-assembly of well-defined coordination polymer (CP) ultrathin films can control the metal complex arrangement and distribution at the molecular level, providing a convenient route for the design and fabrication of novel opto-electrical devices and heterogeneous catalysts. Here, we report the assembly of two series of CP multilayers with the transition-metal ions of Fe2+, Co2+, Zn2+ and Tb3+ as connectors and tripodal terpyridyl ligands of 4,4',4″-(1,3,5-triazine-2,4,6-triyl)tris(1-(4-([2,2':6',2″-terpyridin]-4'-yl)benzyl)pyridin-1-ium) (TerPyTa) and 4,4',4″-(benzene-1,3,5-triyl)tris(1-(4-([2,2':6',2″-terpyridin]-4'-yl)benzyl)pyridin-1-ium) (TerPyBen) as linkers at the air-water interface. The as-prepared Langmuir-Blodgett (LB) films display strong luminescence, with the emission wavelength and relative intensity dependent on both the metal ions and linkers; among them, the Zn-TerPyTa and Zn-TerPyBen CPs give off the strongest luminescent emission centered at about 370 nm with an emission lifetime of approximately 0.2-0.3 ns. The Tb-TerPyTa CPs can give off emission at approximately 490, 546, 586, and 622 nm, attributed to the 5D4 to 7F3-6 electron transitions of typical Tb3+ ions. Finally, these CP LB films can act as efficient heterogeneous photocatalysts for the CO2 reduction to selectively produce CO. The catalytic efficiency can be optimized by adjusting the experimental conditions (light sensitizer, electron donor, and water content) and CP composition (metal ion and ligand) with an excellent yield of up to 248.1 mmol g-1. In particular, it is revealed that, under the same conditions, the catalytic efficiency of the Fe-TerPyTa CP LB film is nearly 2 to 3 orders of magnitude higher than that of the other metalated complexes investigated in the homogeneous system. UV-vis spectroscopy and cyclic voltammetry studies demonstrated that the dual active sites of Fe-terpyridine and TerPyTa units contribute to the enhanced catalytic activity. This work provides an effective method to introduce the earth-abundant metal complexes into CP films to construct efficient noble-metal-free photocatalysts for the CO2 reduction.

Astaxanthin could regulate the gut-kidney axis to mitigate kidney injury in high-fat diet/streptozotocin-induced diabetic mice.

Accumulating evidences have shown the beneficial effects of astaxanthin (AST) supplementation on metabolic diseases prevention and treatment. The goal of present study was to reveal the favorable interactions among AST supplementation, gut microbiota, and kidneys in vivo, so as to attenuate kidney impairment in diabetic mice. Twenty C57BL/6J mice were assigned to a normal control group and a diabetic model group induced by a high-fat diet plus low-dose streptozotocin, and then the diabetic mice were fed with a high-fat diet without or with AST [0.01% (AST_a) or 0.02% (AST_b)] for 12 weeks. When compared to the diabetes kidney disease (DKD) group, AST supplementation delayed the renal pathological progression, reduced fasting blood glucose (AST_b: 1.53-fold, p<0.05), repressed levels of lipopolysaccharide (LPS; AST_a: 1.24-fold, p=0.008; AST_b: 1.43-fold, p<0.001) and TMAO (AST_a: 1.51-fold, p=0.001; AST_b: 1.40-fold, p=0.003), inhibited IL-6 (AST_a: 1.40-fold, p=0.004; AST_b: 1.57-fold, p=0.001) and reactive oxygen species (ROS; AST_a: 1.30-fold, p=0.004; AST_b: 1.53-fold, p<0.001), as well as regulated the Sirt1/PGC-1α/NFκB p65 signaling pathway. Moreover, the results of 16S rRNA gene-based Illumina deep sequencing in each group revealed that dietary AST supplementation also favorably modulated the gut microbiota compared with the DKD group, as evidenced by the inhibition of the harmful bacteria Clostridium_sensu_stricto_1, Romboutsia, and Coriobacteriaceae_UCG-002, and the enhancement of the probiotics such as Lachnospiraceae_NK4A136_group, Roseburia, and Ruminococcaceae. Taken together, dietary AST supplementation could protect kidneys against inflammation and oxidative stress by adjusting the gut-kidney axis in diabetic mice.

Precise Detection on Cell-Cell Fusion by a Facile Molecular Beacon-Based Method.

Cell-cell fusion studies provide an experimental platform for evaluating disease progression and investigating cell infection. However, to realize sensitive and quantitative detection on cell-cell fusion is still a challenge. Herein, we report a facile molecular beacon (MB)-based method for precise detection on cell-cell fusion. By transfection of the spike protein (S protein) and enhanced green fluorescent protein (EGFP) in HEK 293 cells, the virus-mimicking fusogenic effector cells 293-S-EGFP cells were constructed to interact with target cells. Before mixing the effector cells with the target cells, the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) expression in 293-S-EGFP cells was silenced, and the MB for GAPDH mRNA detection was delivered into the GAPDH silenced 293-S-EGFP cells. Once cell-cell fusion occurred, MB migrated from the GAPDH silenced effector cells to the target cells and hybridized with GAPDH mRNA in the target cells to induce fluorescence emission. The cell-cell fusion can be easily visualized and quantitated by fluorescence microscopy and flow cytometry. The fluorescence intensity is strongly dependent on the number of fused target cells. This MB-based method can easily identify the differences in the cell fusions for various target cells with different angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) expression levels, resulting in dramatically different fluorescence intensities in fused target cells. Our study provides a convenient and efficient quantitative detection approach to study cell-cell fusion.

Electronic Structure Regulation of Nickel Phosphide for Efficient Overall Water Splitting.

Rational design and fabrication of efficient and low-cost catalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are crucial for hydrogen production from water electrolysis. Herein, we report heteroatom Fe-incorporated Ni5P4 (Fe-NiP) as an excellent bifunctional catalyst for overall water splitting. Density functional theory (DFT) calculations reveal that heteroatom Fe effectively steers the electronic structure of Ni5P4, which optimizes the hydrogen adsorption behavior. Additionally, the hierarchical conductive framework of Fe-NiP contributes to abundant active sites. Thus, the Fe-NiP catalyst shows robust performance with enhanced intrinsic catalytic activity. As a good bifunctional catalyst, it demands low overpotentials of 144 and 223 mV to deliver a current density of 10 mA cm-2 for HER and OER, respectively. Considering the good bifunctional activity, an outstanding electrolyzer has been successfully assembled, which is superior to the benchmark of a RuO2(+)//Pt/C(-) electrolyzer. This study sheds light on steering the electronic structure of electrocatalysts through a heteroatom modulation strategy.

Clinical features and diagnostic approaches for abdominal tuberculosis: five-year experience from a non-tuberculosis-designated hospital in China.

BACKGROUND AND PURPOSE: abdominal tuberculosis (TB) is a common form of extrapulmonary TB but it is still a diagnostic dilemma in clinical practice. This study aimed to highlight the clinical features and diagnostic approaches for abdominal TB. METHODS: seventy cases of diagnosed abdominal TB were retrospectively collected between August 1st, 2015 and June 30th, 2020. They were classified as peritoneal TB, lymph node TB, gastrointestinal TB, visceral TB or mixed TB. RESULTS: eighteen patients were diagnosed with peritoneal TB, nine with lymph node TB, five with gastrointestinal TB, two with visceral TB and 36 with mixed TB. More than 65 % of the patients had tuberculosis of other sites except the abdomen. The median diagnosis time was 60 days. Ascites (58.6 %), abdominal distension (48.6 %), weight loss (44.3 %) and fever (42.9 %) were the most common symptoms. The overall microbiological and histological detection rates were 70.0 % and 38.6 %, respectively. The non-ascite samples yielded a higher microbiological confirmation rate (63.6 %) than the total samples (40.8 %). Diagnosis was confirmed histologically in 18 patients (69.2 %). Forty-five cases (64.3 %) were clinically diagnosed. Invasive procedures such as surgery (6/7), percutaneous biopsy (7/7) and endoscopy in lymph node TB (4/5) had high confirmation rates. CONCLUSIONS: the diagnosis of abdominal TB should be reached by a combination of clinical, laboratory, radiological, microbiological and pathological findings.

A novel fixed-dose combination treatment for chronic hepatitis C, based on NS5A inhibitor fopitasvir and NS5B inhibitor sofosbuvir.

Drug resistance caused by the extreme genetic variability of zhe hepatitis C virus has rendered effective combinations of drugs indispensable in the treatment of chronic hepatitis C (CHC). Herein, we developed a fixed-dose combination (FDC) treatment containing the NS5B inhibitor sofosbuvir (SOF) and the NS5A inhibitor fopitasvir (FOP). Then the dissolution behavior of FOP in FOP/SOF FDC was improved by co-micronizing FOP with lactose. The enhanced dissolution rate of FOP in the FDC was in good agreement with the behavior of the FOP singledrug tablet. In addition, pharmacokinetic studies showed that both FOP and SOF in the FDC exhibited similar characteristics (area under the curve, Cmax, Tmax, and T1/2) as those of tablets containing FOP or SOF alone. These results revealed that the FOP/SOF FDC represents a potential therapeutic option for the treatment of CHC.

Atypical Oxygen-Bearing Copper Boosts Ethylene Selectivity toward Electrocatalytic CO2 Reduction.

Oxygen-bearing copper (OBC) has been widely studied for enabling the C-C coupling of the electrocatalytic CO2 reduction reaction (CO2RR) since this is a distinctive hallmark of strongly correlated OBC systems and may benefit many other Cu-based catalytic processes. Unresolved problems, however, include the instability of and limited knowledge regarding OBC under realistic operating conditions, raising doubts about its role in CO2RR. Here, an atypical and stable OBC catalyst with a hierarchical pore and nanograin-boundary structure was constructed and was found to exhibit efficient CO2RR for the production of ethylene with a Faradaic efficiency of 45% at a partial current density of 44.7 mA cm-2 in neutral media, and the ethylene partial current density is nearly 26 and 116 times that of oxygen-free copper (OFC) and commercial Cu foam, respectively. More importantly, the structure-activity relationship in CO2RR was explored through a comprehensive analysis of experimental data and computational techniques, thus increasing the fundamental understanding of CO2RR. A systematic characterization analysis suggests that atypical OBC (Cu4O) was formed and that it is stable even at -1.00 V [(vs the reversible hydrogen electrode (RHE)]. Density functional theory calculations show that the atypical OBC enables control over CO adsorption and dimerization, making it possible to implement a preference for the electrosynthesis of ethylene (C2) products. These results provide insight into the synthesis and structural characteristics of OBC as well as its interplay with ethylene selectivity.

Design, synthesis and structure-activity relationship study of piperazinone-containing thieno[3,2-d]pyrimidine derivatives as new PI3Kδ inhibitors.

Two classes of piperazinone-containing thieno[3,2-d]pyrimidines were designed and synthesized as new PI3Kδ inhibitors in this study. Detailed SAR study with respect to the piperazinone substituents at the 6-position of thieno[3,2-d]pyrimidine core demonstrated that piperazinone-containing thieno[3,2-d]pyrimidines would be more potent and selective for PI3Kδ than their piperazine counterparts, which led to the discovery of several potent PI3Kδ inhibitors with comparable or better antiproliferative activity against a panel of non-Hodgkin lymphoma (NHL) cell lines as compared with idelalisib. Our study will promote the development of new PI3Kδ inhibitors based on piperazinone-containing thieno[3,2-d]pyrimidine scaffold.

Identification of a potent and selective phosphatidylinositol 3-kinase δ inhibitor for the treatment of non-Hodgkin's lymphoma.

PI3Kδ has proved to be an effective target for anti-lymphoma drugs. However, the application of current approved PI3Kδ inhibitors has been greatly limited due to their specific immune-mediated toxicity and increased risk of infection, it is necessary to develop more PI3Kδ inhibitors with new scaffold. In this study, SAR study with respect to piperazinone-containing purine derivatives led to the discovery of a potent and selective PI3Kδ inhibitor, 4-(cyclobutanecarbonyl)-1-((2-(2-ethyl-1H-benzo[d]imidazol-1-yl)-9-methyl-6-morpholino-9H-purin-8-yl)methyl)piperazin-2-one (WNY1613). WNY1613 exhibits good antiproliferative activity against a panel of non-Hodgkin's lymphoma (NHL) cell lines by inducing cancer cell apoptosis and inhibiting the phosphorylation of PI3K and MAPK downstream components. In addition, it can also prevent the tumor growth in both SU-DHL-6 and JEKO-1 xenograft models without observable toxicity. WNY1613 thus could be developed as a promising candidate for the treatment of NHL after subsequent extensive pharmacodynamics and pharmacokinetics investigation.

[Study on improvement and mechanism of tableting properties of porous Fagopyri Dibotryis Rhizoma powders].

At present, there are many difficulties in the development and production of traditional Chinese medicine(TCM) tablets. This work aimed to explore the feasibility of improving dissolution difficulty and large dosage of TCM tablets by co-spray drying TCM extract with a small amount of pore-foaming agent ammonium bicarbonate. A series of porous Fagopyri Dibotryis Rhizoma powders were prepared by co-spray drying Fagopyri Dibotryis Rhizoma with different amounts of ammonium bicarbonate, and their powder pro-perties and tablet properties were comparatively investigated. At the same time, Fagopyri Dibotryis Rhizoma commercial tablets and raw material tablets were used as control drugs, the improvement degree of its compressibility and dissolution rate was investigated. The results showed that there were higher porosity, specific surface area and hollow spheroidal particles structure of powders via co-spray drying Fagopyri Dibotryis Rhizoma with NH_4HCO_3. Compared to parent and commercial Fagopyri Dibotryis Rhizoma tablets, the dissolution rates and compressibility of porous Fagopyri Dibotryis Rhizoma tablets were significantly increasing. High compressibility could increase drug loading by reducing excipients in manufacturing of tablets and lower the dose of Fagopyri Dibotryis Rhizoma tablets.

Highly Efficient Hydrogen Evolution from a Mesoporous Hybrid of Nickel Phosphide Nanoparticles Anchored on Cobalt Phosphosulfide/Phosphide Nanosheet Arrays.

Facile design of low-cost and high-efficiency catalysts with earth-abundant and cheap materials is desirable to replace platinum (Pt) for the hydrogen evolution reaction (HER) in water splitting, but the development of such HER catalysts with Pt-like activity using simple strategies remains challenging. A mesoporous hybrid catalyst of nickel phosphides nanoparticles and cobalt phosphosulfide/phosphide (CoS|Ni|P) nanosheet arrays for HER is reported here, which is developed by a facile three-step approach consisting of electrodeposition, thermal sulfurization, and phosphorization. This hybrid catalyst is highly robust and stable in acid for HER, and is distinguished by very low overpotentials of 41, 88, and 150 mV to achieve 10, 100, and 1000 mA cm-2 , respectively, as well as a small Tafel slope (45.2 mV dec-1 ), and a large exchange current density (964 µA cm-2 ). It is among the most efficient earth-abundant catalysts reported thus far for HER. More importantly, this electrocatalyst has electrochemical durability over 20 h under a wide range of current densities (up to 1 A cm-2 ) in acidic conditions, as well as very high turnover frequencies of 0.40 and 1.26 H2 s-1 at overpotentials of 75 and 100 mV, respectively, showing that it has great potential for practical applications in large-scale water electrolysis.

Design, synthesis and biological evaluation of 3,5-dimethylisoxazole and pyridone derivatives as BRD4 inhibitors.

Bromodomain-containing protein 4 (BRD4), a member of the bromodomain and extra-terminal (BET) family, has been recognized as an attractive candidate target for the treatment targeting gene transcription in several types of cancers. In this study, two types of novel compounds were designed, synthesized and evaluated as BRD4 inhibitors. Therein, pyridone derivatives were more effective against BRD4 protein and human leukemia cell lines MV4-11. Among them, compounds 11d, 11e and 11f were the most potential ones with IC50 values of 0.55 µM, 0.86 µM and 0.80 µM against BRD4, and exhibited remarkable antiproliferative activities against MV4-11 cells with IC50 values of 0.19 µM, 0.32 µM and 0.12 µM, respectively. Moreover, in western blot assay, compound 11e induced down-regulation of C-Myc, which is a significant downstream gene of BRD4. Cell cycle analysis assay also showed that compound 11e could block MV4-11 cells at G0/G1 phase. Taken together, our results suggested that compound 11e and its derivatives were a class of novel structural potential BRD4 inhibitors and could serve as lead compounds for further exploration.

Discovery and evaluation of novel nitrodihydroimidazooxazoles as promising anti-tuberculosis agents.

New analogues of antitubercular drug Delamanid were prepared, seeking drug candidates with enhanced aqueous solubility and high efficacy. The strategy involved replacement of phenoxy linker proximal to the 2-nitroimidazooxazole of Delamanid by piperidine fused 5 or 6-membered ring heterocycles (ring A). The new compounds were all more hydrophilic than Delamanid, and several class of analogues showed remarkable activities against M. bovis. And among these series, the tetrahydro-naphthyridine-linked nitroimidazoles displayed excellent antimycobacterial activity against both replicating (MABA) and nonreplicating (LORA) M. tb H37Rv and low cytotoxicity. Compared to Delamanid, these new compounds (6, 7, 45) demonstrated dramatically improved physicochemical properties and are suitable for further in vitro and in vivo evaluation.

Discovery and Structure-Resistance Relationship Study of New Thieno[2,3-b] Pyridine HCV NS4B Inhibitors.

The non-structural protein 4B (NS4B) of hepatitis C virus (HCV) has emerged as a promising target for chronic hepatitis C treatment. The thieno[2,3-b]pyridine HCV inhibitor 2 has demonstrated properties as a NS4B inhibitor. Subsequent hybridization of 2 with our recently published imidazo[2,1-b]thiazole NS4B inhibitor 3 resulted in the discovery of several more potent compounds with sub-micromolar EC50 against HCV genotype 1b replicon. More importantly, the resistant profile study of the new synthesized HCV inhibitors illustrated that the bicyclic scaffold would mediate the resistance of H3R and Q26R mutations, while the piperazinone motif would mediate the resistance of H94R, F98C and V105M mutations, and the C3- amino group would disrupt the interaction between piperazinone motif and NS4B. This structure-resistance relationship detail could help us to develop new NS4B inhibitors with higher resistant barrier in the future.

Metabolism of SKLB-TB1001, a Potent Antituberculosis Agent, in Animals.

Tuberculosis is a major global health problem, and the emergence of multidrug-resistant and extensively drug-resistant strains has increased the difficulty of treating this disease. Among the novel antituberculosis drugs in the pipeline, decaprenylphosphoryl-beta-d-ribose-2-epimerase (DprE1) inhibitors such as BTZ043 and pBTZ169 exhibited extraordinary antituberculosis potency. Here, the metabolites of the new DprE1 inhibitor SKLB-TB1001 in vivo and its inhibition of cytochrome P450 isoforms and plasma protein binding (PPB) in vitro were studied. The results showed that rapid transformation and high PPB resulted in inadequate exposure in vivo and thus led to the moderate potency of SKLB-TB1001 in vivo This study provided explanations for the discrepant potency of this scaffold in vivo and in vitro Meanwhile, it also provides a rationale for lead optimization of this very promising scaffold of antituberculosis agents to prevent them from being metabolized, thus improving their exposure in vivo.

Poly(sodium 4-styrenesulfonate) Stabilized Janus Nanosheets in Brine with Retained Amphiphilicity.

Maintaining colloidal stability in unfriendly environments while retaining surface chemical properties is challenging for fundamental science and crucial for many applications. Here, we report for the first time that by using a low concentration of poly(sodium 4-styrenesulfonate) (PSS), graphene-based amphiphilic Janus nanosheets (AJNs) can be stabilized in high salt brine (3 wt % NaCl and 0.5 wt % CaCl2), whereas the interfacial behavior of the nanosheets is not affected. The adsorption of PSS on the hydrophilic and hydrophobic surfaces of AJNs in brine was investigated experimentally and by molecular dynamics simulations. Simulations further showed that the spatial configuration of absorbed PSS molecules with sulfonate functional groups facing outward favored the generation of electrosteric repulsive interactions. Calculations of the interaction energy between PSS molecules and the nanosheet revealed surface charge as a key parameter to stabilize AJNs in the salt environment, as demonstrated by the case of graphene oxide with higher surface charge. Simulations were also used to examine the interfacial behavior of graphene-based AJNs in biphasic systems. The AJNs, which exhibited asymmetry in surface wettability, remained at the oil/brine interface because of PSS detachment from the hydrophobic surface. The results were subsequently experimentally confirmed, consistent with our previously reported graphene-based AJN fluid prepared in fresh water. The process was thermodynamically supported by the demonstrated negative change of Gibbs free energy. We believe that such a strategy could benefit for the stabilization of other AJNs with surface chemical accessibility under harsh conditions.

The predictive value of hunger score on gastric evacuation after oral intake of carbohydrate solution.

BACKGROUND: Surgical patients are asked to fast for a sufficient duration to ensure that the amount of residual liquid in the stomach is within the safe range, thereby reducing the risk of gastric reflux perioperatively. The authors hypothesized that subjective hunger numerical rating scale (NRS) score could also help assess the process of gastric emptying and determine the amount of fluid remaining in the stomach. METHODS: The current study consisted of healthy volunteers recruited by advertisement and mutual introduction. Participants were asked to rate their subjective hunger feeling every 30 min after oral administration of 8 mL/kg carbohydrate nutrient solution that contained 10% maltodextrin and 2.5% sucrose. Consecutively, the gastric residual fluid was measured by magnetic resonance imagining (MRI). The Spearman's correlation coefficient, the ROC curves and the stepwise regression were used to analyze the predictive value of NRS for the gastric emptying process. RESULTS: The cohort consisted of 29 healthy volunteers enrolled in this study. The area under ROC curves estimated by the NRS score for the gastric residual volume of 2 mL/kg, 1 mL/kg, and 0.5 mL/kg were AUC2.0 = 0.78, AUC1.0 = 0.76, and AUC0.5 = 0.72, respectively. The correlation coefficient between the NRS score and the residual liquid in the stomach was -0.57 (P < 0.01). The correlation coefficient between the increase of the NRS score and the decrease of gastric liquid residual volume was 0.46 (P < 0.01). The standardized estimate of NRS score for the residual volume was -0.18 (P < 0.01) and the standardized estimate of fasting time was -0.73 (P < 0.01). CONCLUSIONS: The subjective hunger NRS score can not accurately predict the gastric residual volume, but it can provide a reference for clinicians to judge the gastric emptying process and it should be used as a second check after oral intake of clear fluids before surgery according to the new fasting protocol.

[Research on Exact Location Algorithm of Pupil Center Based on Ellipse Fitting].

In order to realize the requirement of precise eye tracking in clinical, a pupil center location algorithm based on the least square method is proposed. First, the eye image was captured by the camera under the infrared light, and then the two-valued image was obtained after preprocessing. Use the number of pixels that form the outline which was Extracting from the two-valued image to carry out the rough filtration of the pupil. The ellipse curve was fitting by the randomly select 6 pixels on the filtered contours, and then calculated the variance of distance between the center and the edge of the ellipse. The ellipse center is ellipse center, where the variance of the distance is Minimum. The algorithm has advantage of accurate identification the pupil center when there is white spot interference and squint. Experiments show that the pupil center can be located quickly and real-timely by this algorithm.