Pivotal Role of Geometry Regulation on O-O Bond Formation Mechanism of Bimetallic Water Oxidation Catalysts.

In this study, we highlight the impact of catalyst geometry on the formation of O-O bonds in Cu2 and Fe2 catalysts. A series of Cu2 complexes with diverse linkers are designed as electrocatalysts for water oxidation. Interestingly, the catalytic performance of these Cu2 complexes is enhanced as their molecular skeletons become more rigid, which contrasts with the behavior observed in our previous investigation with Fe2 analogs. Moreover, mechanistic studies reveal that the reactivity of the bridging O atom results in distinct pathways for O-O bond formation in Cu2 and Fe2 catalysts. In Cu2 systems, the coupling takes place between a terminal CuIII -OH and a bridging µ-O⋅ radical. Whereas in Fe2 systems, it involves the coupling of two terminal Fe-oxo entities. Furthermore, an in-depth structure-activity analysis uncovers the spatial geometric prerequisites for the coupling of the terminal OH with the bridging µ-O⋅ radical, ultimately leading to the O-O bond formation. Overall, this study emphasizes the critical role of precisely adjusting the spatial geometry of catalysts to align with the O-O bonding pathway.

Methylated Septin9 has moderate diagnostic value in colorectal cancer detection in Chinese population: a multicenter study.

BACKGROUND: The detection rate of methylated Septin9 (mSEPT9) in colorectal cancer (CRC) is varied greatly across the studies. This study aimed to evaluate the diagnostic ability of mSEPT9 in CRC, and compare the diagnostic efficacy with fecal immunochemical test (FIT). METHODS: 326 subjects from four centers were prospectively recruited, including 179 CRC and 147 non-CRC subjects. The plasma was collected for mSEPT9 and CEA, AFP, CA125, CA153 and CA199 test, and fecal samples for FIT tests. Sensitivity, specificity and area under the curve (AUC) of receiver operating characteristic curve were calculated to evaluate the diagnostic value of each biomarker. RESULTS: The positive rate in mSEPT9 and FIT, and the level of CEA, CA125 and CA199 were significantly higher in CRC compared with non-CRC subjects. The mSEPT9 positive rate was not associated with TNM stage and tumor stage. The sensitivity, specificity and AUC of mSEPT9 in diagnostic CRC were 0.77, 0.88 and 0.82, respectively, while the value in FIT was 0.88, 0.80 and 0.83, respectively. mSEPT9 and FIT have higher AUC value than that of CEA, CA125 and CA199. Combination of both mSEPT9 and FIT positive increased sensitivity and AUC to 0.98 and 0.83, respectively, but the specificity was declined. mSEPT9 has a slightly low sensitivity in diagnosis of colon cancer (0.87) compared with rectal cancer (0.93). CONCLUSION: mSEPT9 demonstrated moderate diagnostic value in CRC detection, which was similar to the FIT but superior to the CEA, CA125 and CA199. Combination of mSEPT9 and FIT further improved diagnostic sensitivity in CRC. TRIAL REGISTRATION: ChiCTR2000038319.

Ranking-Based Salient Object Detection and Depth Prediction for Shallow Depth-of-Field.

Shallow depth-of-field (DoF), focusing on the region of interest by blurring out the rest of the image, is challenging in computer vision and computational photography. It can be achieved either by adjusting the parameters (e.g., aperture and focal length) of a single-lens reflex camera or computational techniques. In this paper, we investigate the latter one, i.e., explore a computational method to render shallow DoF. The previous methods either rely on portrait segmentation or stereo sensing, which can only be applied to portrait photos and require stereo inputs. To address these issues, we study the problem of rendering shallow DoF from an arbitrary image. In particular, we propose a method that consists of a salient object detection (SOD) module, a monocular depth prediction (MDP) module, and a DoF rendering module. The SOD module determines the focal plane, while the MDP module controls the blur degree. Specifically, we introduce a label-guided ranking loss for both salient object detection and depth prediction. For salient object detection, the label-guided ranking loss comprises two terms: (i) heterogeneous ranking loss that encourages the sampled salient pixels to be different from background pixels; (ii) homogeneous ranking loss penalizes the inconsistency of salient pixels or background pixels. For depth prediction, the label-guided ranking loss mainly relies on multilevel structural information, i.e., from low-level edge maps to high-level object instance masks. In addition, we introduce a SOD and depth-aware blur rendering method to generate shallow DoF images. Comprehensive experiments demonstrate the effectiveness of our proposed method.

Ferric Uptake Regulator Provides a New Strategy for Acidophile Adaptation to Acidic Ecosystems.

Acidophiles play a dominant role in driving elemental cycling in natural acid mine drainage (AMD) habitats and exhibit important application value in bioleaching and bioremediation. Acidity is an inevitable environmental stress and a key factor that affects the survival of acidophiles in their acidified natural habitats; however, the regulatory strategies applied by acidophilic bacteria to withstand low pH are unclear. We identified the significance of the ferric uptake regulator (Fur) in acidophiles adapting to acidic environments and discovered that Fur is ubiquitous as well as highly conserved in acidophilic bacteria. Mutagenesis of the fur gene of Acidithiobacillus caldus, a prototypical acidophilic sulfur-oxidizing bacterium found in AMD, revealed that Fur is required for the acid resistance of this acidophilic bacterium. Phenotypic characterization, transcriptome sequencing (RNA-seq), mutagenesis, and biochemical assays indicated that the Acidithiobacillus caldus ferric uptake regulator (AcFur) is involved in extreme acid resistance by regulating the expression of several key genes of certain cellular activities, such as iron transport, biofilm formation, sulfur metabolism, chemotaxis, and flagellar biosynthesis. Finally, a Fur-dependent acid resistance regulatory strategy in A. caldus was proposed to illustrate the ecological behavior of acidophilic bacteria under low pH. This study provides new insights into the adaptation strategies of acidophiles to AMD ecosystems and will promote the design and development of engineered biological systems for the environmental adaptation of acidophiles.IMPORTANCE This study advances our understanding of the acid tolerance mechanism of A. caldus, identifies the key fur gene responsible for acid resistance, and elucidates the correlation between fur and acid resistance, thus contributing to an understanding of the ecological behavior of acidophilic bacteria. These findings provide new insights into the acid resistance process in Acidithiobacillus species, thereby promoting the study of the environmental adaptation of acidophilic bacteria and the design of engineered biological systems.

Alteration in microRNA-155 level correspond to severity of coronary heart disease.

Cardiovascular diseases are a consequence of genetic and epigenetic interactions. Inflammation contributes toward the initiation and progression of atherosclerotic lesions. Previous studies have shown that microRNA (miR) 155 plays a role in cardiovascular disease, including the prevention of inflammatory infiltration, regulation of autophagy, and participation of immunoreactions. However, the change of miR-155 level in the development of atherosclerosis remains to be determined. The initial objective of this study was that CHD patients would have altered serum miR-155 level. We also aim to identify whether circulating miR-155 content could be used as a predictor for severity of coronary atherosclerosis. Sample was collected from 300 CHD patients and 100 controls. Quantitative real-time PCR analysis was utilized on RNA isolated from plasma. Expression of miR-155 was identified on the basis of the quartiles of the Gensini score, and association between the microRNA and CHD was analyzed. CHD patients had higher miR-155 level in comparison to controls (p < .001), and the miRNA content significantly increased following an increasing Gensini score (p < .001). Gensini score was significantly associated with miR-155 expression (r = 0.6124, p < .001). Our findings suggest that interaction between circulating miR-155 expressions with classical risk factors of atherosclerotic lesions, and serum miR-155 content may serve as a novel biomarker for evaluating severity of CHD.

[Analysis of different forms Linderae Radix based on HPLC and NIRS fingerprints].

Three different forms of Linderae Radix were evaluated by HPLC combined with NIRS fingerprint. The Linderae Radix was divided into three forms, including spindle root, straight root and old root. The HPLC fingerprints were developed, and then cluster analysis was performed using the SPSS software. The near-infrared spectra of Linderae Radix was collected, and then established the discriminant analysis model. The similarity values of the spindle root and straight root all were above 0.990, while the similarity value of the old root was less than 0.850. Two forms of Linderae Radix were obviously divided into three parts by the NIRS model and Cluster analysis. The results of HPLC and FT-NIR analysis showed the quality of Linderae Radix old root was different from the spindle root and straight root. The combined use of the two methods could identify different forms of Linderae Radix quickly and accurately.

Role of plasmacytoid dendritic cells and inducible costimulator-positive regulatory T cells in the immunosuppression microenvironment of gastric cancer.

Regulatory T cells (Tregs) and plasmacytoid dendritic cells (pDCs) play important roles in the immune escape of cancer. In this study, we investigated pDCs and pDC-induced inducible costimulator (ICOS)(+) Treg populations in peripheral blood from gastric cancer (GC) patients and healthy donors by flow cytometry. The distribution of these cells in carcinoma tissue, peritumor tissue, and normal gastric mucosa was detected by immunohistochemistry. Plasma and tissue concentration of the cytokines such as interleukin-10 and transforming growth factor-ß1 were also measured. We found that the numbers of pDCs, Tregs, and ICOS(+) Tregs in peripheral blood were increased in GC patients compared with healthy donors. In tissue, Tregs and ICOS(+) Tregs were found distributing mainly in carcinoma tissue, whereas pDCs were mainly found in peritumor tissue. Moreover, the Foxp3(+) ICOS(+) /Foxp3(+) cell ratio in carcinoma and peritumor tissue were higher than that in normal tissue. There were more ICOS(+) Tregs in tumor and peritumor tissue of late-stage GC patients. There was a positive correlation between pDCs and ICOS(+) Tregs in peripheral blood and peritumor tissue from GC patients. In conclusion, pDCs may play a potential role in recruiting ICOS(+) Tregs, and both participate in the immunosuppression microenvironment of GC.

Mechanistic research: Selenium regulates virulence factors, reducing adhesion ability and inflammatory damage of Helicobacter pylori.

BACKGROUND: The pathogenicity of Helicobacter pylori is dependent on factors including the environment and the host. Although selenium is closely related to pathogenicity as an environmental factor, the specific correlation between them remains unclear. AIM: To investigate how selenium acts on virulence factors and reduces their toxicity. METHODS: H. pylori strains were induced by sodium selenite. The expression of cytotoxin-associated protein A (CagA) and vacuolating cytotoxin gene A (VacA) was determined by quantitative PCR and Western blotting. Transcriptomics was used to analyze CagA, CagM, CagE, Cag1, Cag3, and CagT. C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction, and H. pylori colonization, inflammatory reactions, and the cell adhesion ability of H. pylori were assessed. RESULTS: CagA and VacA expression was upregulated at first and then downregulated in the H. pylori strains after sodium selenite treatment. Their expression was significantly and steadily downregulated after the 5th cycle (10 d). Transcriptome analysis revealed that sodium selenite altered the levels affect H. pylori virulence factors such as CagA, CagM, CagE, Cag1, Cag3, and CagT. Of these factors, CagM and CagE expression was continuously downregulated and further downregulated after 2 h of induction with sodium selenite. Moreover, CagT expression was upregulated before the 3rd cycle (6 d) and significantly downregulated after the 5th cycle. Cag1 and Cag3 expression was upregulated and downregulated, respectively, but no significant change was observed by the 5th cycle. C57BL/6A mice were infected with the attenuated strains subjected to sodium selenite induction. The extent of H. pylori colonization in the stomach increased; however, sodium selenite also induced a mild inflammatory reaction in the gastric mucosa of H. pylori-infected mice, and the cell adhesion ability of H. pylori was significantly weakened. CONCLUSION: These results demonstrate that H. pylori displayed virulence attenuation after the 10th d of sodium selenite treatment. Sodium selenite is a low toxicity compound with strong stability that can reduce the cell adhesion ability of H. pylori, thus mitigating the inflammatory damage to the gastric mucosa.

Anti-tumor effects of Mfn2 in gastric cancer.

Mitofusin-2 (Mfn2) is a mitochondrial outer membrane protein involved in mitochondrial fusion. Its mutation can cause Charcot-Marie-Tooth disease. Recent studies of Mfn2 in cancer research have not included gastric cancer. We confirmed that Mfn2 expression was lower in tumor tissue than in normal gastric mucosal tissue and that it was negatively correlated with tumor size, indicating an anti-tumor role for Mfn2. In vitro experiments showed that Mfn2 overexpression suppressed gastric cancer cell proliferation and colony formation, weakened the invasion and migratory ability of cancer cells by downregulating MMP-2 and MMP-9, halted the cell cycle and induced apoptosis. Western blotting indicated the likely involvement of P21 and PI3K/Akt signaling. Therefore, Mfn2 is a potential anti-tumor gene and a potential therapeutic target for treating gastric cancer. The progress of gastric cancer may be delayed by controlling Mfn2 expression.

[Effects of intrauterine cigarette smoking exposure on expression of 3-mercaptopyruvate sulfurtransferase in medulla oblongata of neonatal rats].

OBJECTIVE: To investigate the expression of 3-mercaptopyruvate sulfurtransferase (3MST) in medulla oblongata of neonatal rats and effects of intrauterine cigarette exposure on its expression. METHODS: Sprague Dawley pregnant rats were randomly divided into 2 groups, control group and cigarette smoke exposure group (n = 8). 3MST mRNA and protein expression in medulla oblongata of neonatal rats were analysed by RT-PCR and Western blot, respectively, and the expression of 3MST in the neurons of respiratory-related nuclei in medulla oblongata of neonatal rats was investigated with immunohistochemical technique. RESULTS: The RT-PCR and Western blot analyses showed that 3MST mRNA and protein were expressed in the medulla oblogata of neonatal rats and intrauterine cigarette exposure promoted their expression (P < 0.05). Immunohistochemical staining indicated that 3MST existed in the neurons of pre-Bötzinger complex (pre-BötC), hypoglossal nucleus (12N), ambiguous nucleus (Amb), facial nucleus (FN) and nucleus tractus solitarius (NTS) in control group of the animals and the mean optical densities of 3MST-positive neurons in the pre-BötC, 12N, Amb and FN, but not NTS, were significantly increased in cigarette smoke exposure group (P < 0.05). CONCLUSIONS: 3MST exists in the neurons of medullary respiratory nuclei of neonatal rats and its expression can be up-regulated by intrauterine cigarette exposure, suggesting that the 3MST-H2S pathway may be involved in protection of medullary respiratory centers against injury induced by intrauterine cigarette exposure.

[Determination of main active components in crude and processed Corydalis Rhizoma samples from different habitats].

OBJECTIVE: To compare the content of water, ethanol soluble extracts and tetrahydropalmatine in crude and processed Corydalis Rhizoma samples from different habitats. METHODS: Corydalis Rhizoma was processed according to the optimum processing of the Chinese Pharmacopoeia (2010 edition), and then, the difference of the content of water,ethanol soluble extracts and tetrahydropalmatine in crude and processed Corydalis Rhizoma samples were analyzed and compared. RESULTS: From 14 different batches of Corydalis Rhizoma studies, the content of water, ethanol soluble extracts and tetrahydropalmatine in crude Corydalis Rhizoma was 12.8%-14.8%, 16.5%-19.6% and 0.043%-0.075%, respectively; As for Corydalis Rhizoma after processing with vinegar,the content of water, ethanol soluble extracts and tetrahydropalmatine was 7.58%-11.7%, 17.8%-23.5% and 0.046%-0.079%, respectively. CONCLUSION: The content of water, ethanol soluble extracts and tetrahydropalmatine varies slightly in the same type of samples from different habitats,which might be due to the difference in soil and climate in each habitat.

Analysis of high risk factors for chronic atrophic gastritis.

Background: Screening for chronic atrophic gastritis (CAG) is crucial for the prevention and early detection of gastric cancer. Endoscopy is the main method of CAG diagnosis, with high training requirements and limited accuracy, making it difficult to popularize. The study attempts to improve the positive rate and accuracy of CAG screening through non-invasive testing. Methods: A total of 2564 patients who underwent gastroscopy were included in this study. The results of gastroscopic evaluation, histological biopsy results (including H. pylori biopsy), urea breath test (UBT) results, serum pepsinogen, and testosterone were statistically analyzed. Results: We found significant differences in the diagnosis of CAG between endoscopy and histological biopsy. Pepsinogen II and pepsinogen I/II ratio were more useful for the diagnosis of CAG compared with pepsinogen I. The risk of CAG was increased when pepsinogen II exceeded 11.05 µg/L, and the pepsinogen I/II ratio was less than 3.75. CAG positivity was higher in patients with positive H. pylori infection on UBT screening. In addition, higher levels of testosterone, SHBG and HSD17B2, and lower level of GNRH1 were found in CAG mucosa. Patients with high serum testosterone had a higher risk of CAG. Conclusion: CAG screening should be combined with endoscopic evaluation, biopsy, and other non-invasive tests. Non-invasive tests include the combination of serum pepsinogen II protein and pepsinogen I/II ratio and high level of serum testosterone. UBT combined with serum pepsinogen testing may improve the positive rate of CAG and reduce gastric mucosal damage from multiple biopsies.

[QMEC-based Analysis of the Soil Microbial Functional Potentials across Different Tibetan Plateau Glacier Forelands].

Soil microorganisms dominate the biogeochemical cycles of elements in glacier forelands, which continue to expand due to the climate warming. We analyzed the soil microbial functional characteristics among three types of glacier forelands on the Tibetan Plateau: Yulong Glacier (Y), a temperate glacier; Tianshan Urumqi Glacier No.1 (T), a sub-continental glacier; and Laohugou Glacier No.12 (L), a continental glacier. Here, soil microbial functional genes were quantified using quantitative microbial element cycling technology (QMEC). We found that, in the three glacier forelands, the abundances of soil microbial functional genes related to hemicellulose degradation and reductive acetyl-CoA pathway were highest compared with other carbon-related functional genes. The main nitrogen cycling genes were involved in ammonification. The functional genes of the phosphorus cycle and sulfur cycle were related to organic phosphate mineralization and sulfur oxidation. Furthermore, the soils of the temperate glacier foreland with better hydrothermal conditions had the most complex microbial functional gene structure and the highest functional potentials, followed by those of the soils of continental glacier foreland with the driest environment. These significant differences in soil microbial functional genes among the three types of glacier forelands verified the impacts of geographic difference on microbial functional characteristics, as well as providing a basis for the study of soil microbial functions and biogeochemical cycles in glacier forelands.

Extraction of brown pigment from Rosa laevigata and its antioxidant activities.

CONTEXT: Rosa laevigata Michx. (Rosaceae), widespread in China, contains many valuable nutrients and has long been used as food and medicine in Chinese folklore. Nowadays, due to its favorable property of coloring, the brown pigment of R. laevigata has an attractive potential as an available additive in food. OBJECTIVE: The aims of this study were to optimize the extraction process of brown pigment from R. laevigata and investigate its antioxidant activities on the basis of its abilities to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical and superoxide radical. MATERIALS AND METHODS: Extraction conditions of brown pigment from R. laevigata were investigated through an orthogonal design of L9(3)4 assay. Ethanol concentration, extraction temperature, time, and ratio of material to solvent were the main factors affecting the extraction rate. Subsequently, the antioxidant activity of brown pigment was assessed using DPPH method, while hydroxyl radicals and superoxide free radicals were respectively determined by the Fenton-RhB (Rhodamine B) system and using the pyrogallol-luminol system. RESULTS: The optimum extraction conditions were determined: temperature 70°C, ethanol concentration was 60%, extraction time 2 h and ratio of material to solvent was 1:6. Brown pigment showed a good radical scavenging activity, and exhibited a concentration-dependent inhibition of hydroxyl radical and superoxide free radical at low concentrations. When the concentration of brown pigment was 1 mg/mL, the scavenging percentage of hydroxyl radical reached 67.33%. DISCUSSION AND CONCLUSION: The brown pigment of R. laevigata could potentially be used as a promising natural antioxidant in the food and pharmaceutical industries.

A Performance Evaluation of Correspondence Grouping Methods for 3D Rigid Data Matching.

Seeking consistent point-to-point correspondences between 3D rigid data (point clouds, meshes, or depth maps) is a fundamental problem in 3D computer vision. While a number of correspondence selection methods have been proposed in recent years, their advantages and shortcomings remain unclear regarding different applications and perturbations. To fill this gap, this paper gives a comprehensive evaluation of nine state-of-the-art 3D correspondence grouping methods. A good correspondence grouping algorithm is expected to retrieve as many as inliers from initial feature matches, giving a rise in both precision and recall as well as facilitating accurate transformation estimation. Toward this rule, we deploy experiments on three benchmarks with different application contexts, including shape retrieval, 3D object recognition, and point cloud registration. We also investigate various perturbations such as noise, point density variation, clutter, occlusion, partial overlap, different scales of initial correspondences, and different combinations of keypoint detectors and descriptors. The rich variety of application scenarios and nuisances result in different spatial distributions and inlier ratios of initial feature correspondences, thus enabling a thorough evaluation. Based on the outcomes, we give a summary of the traits, merits, and demerits of evaluated approaches and indicate some potential future research directions.

Early genetic diagnosis of clarithromycin resistance in Helicobacter pylori.

BACKGROUND: The drug resistance rate of clinical Helicobacter pylori (H. pylori) isolates has increased. However, the mechanism of drug resistance remains unclear. In this study, drug-resistant H. pylori strains were isolated from different areas and different populations of Chinese for genomic analysis. AIM: To investigate drug-resistant genes in H. pylori and find the genes for the early diagnosis of clarithromycin resistance. METHODS: Three drug-resistant H. pylori strains were isolated from patients with gastritis in Bama County, China. Minimal inhibitory concentrations of clarithromycin, metronidazole, and levofloxacin were determined and complete genome sequencing was performed with annotation. Hp1181 and hp1184 genes were found in these strains and then detected by reverse transcription polymerase chain reaction. The relationships between hp1181 or hp1184 and clarithromycin resistance were ascertained with gene mutant and drug-resistant strains. The homology of the strains with hp26695 was assessed through complete genome detection and identification. Differences in genome sequences, gene quantity, and gene characteristics were detected amongst the three strains. Prediction and analysis of the function of drug-resistant genes indicated that the RNA expression of hp1181 and hp1184 increased in the three strains, which was the same in the artificially induced clarithromycin-resistant bacteria. After gene knockout, the drug sensitivity of the strains was assessed. RESULTS: The strains showing a high degree of homology with hp26695, hp1181, and hp1184 genes were found in these strains; the expression of the genes hp1184 and hp1181 was associated with clarithromycin resistance. CONCLUSION: Hp1181 and hp1184 mutations may be the earliest and most persistent response to clarithromycin resistance, and they may be the potential target genes for the diagnosis, prevention, and treatment of clarithromycin resistance.

Application of traditional Chinese medicine in treatment of Helicobacter pylori infection.

Helicobacter pylori (H. pylori) has a high rate of infection and antibiotic resistance and poses a serious threat to human life. One of the main strategies to overcome drug resistance is to develop new treatment plans. Traditional Chinese medicine (TCM) that is commonly used to treat many diseases in China can reduce drug resistance and increase the eradication rate of H. pylori. In this paper, we review the research progress on TCM in the treatment of H. pylori infection. The mechanism of action of TCM is reviewed and research and applications of TCM in the treatment of H. pylori are demonstrated. Finally, we discuss problems confronting the use of TCM for the treatment of H. pylori infection and propose possible solutions. In addition, the plans of TCM in H. pylori treatment were also screened: Dampness-heat syndrome in the spleen and stomach, deficiency of spleen and stomach, and cold-heat complicated syndrome, and the effective components therein are studied. The antibacterial effect of TCM is relatively slow; for rapid improvement of the treatment effect of refractory H. pylori gastritis, we provide an appropriate treatment regime combining TCM and Western medicine with immune-regulatory and synergistic antibacterial effects.

Efficient synthesis of natural polyphenolic stilbenes: resveratrol, piceatannol and oxyresveratrol.

The practical synthesis of important natural polyphenolic stilbenes, including resveratrol, piceatannol and oxyresveratrol, through Perkin methodology is described. Starting from 3,5-dihydoxyacetophenone (1), the common intermediate 3,5-dimethoxyphenylacetic acid (3) can be obtained via methylation and Willgerodt-Kindler reaction. Perkin condensations between (3) and substituted phenylaldehydes 4 furnished E-2,3-diarylacrylic acids 5, followed by decarboxylation in Cu/quinoline giving stilbene intermediates 6 which bear the Z-configuration. Finally, through a simultaneous demethylation/isomerization process in AlI3/CH3CN system, the target compounds 7a-c can be obtained respectively in good to high overall yields. The synthetic method proved to be more concise, trans-specific, mild, economical and commonly applicable.

Image Feature Correspondence Selection: a Comparative Study and a New Contribution.

Image feature correspondence selection is pivotal to many computer vision tasks from object recognition to 3D reconstruction. Although many correspondence selection algorithms have been developed in the past decade, there still lacks an in-depth evaluation and comparison in the open literature, which makes it difficult to choose the appropriate algorithm for a specific application. This paper attempts to fill this gap by evaluating eight competing correspondence selection algorithms including both classical methods and current state-of-the-art ones. In addition to preselected correspondences, we have compared different combinations of detector and descriptor on four standard datasets. The diversity of those datasets cover a wide range of uncertainty factors including zoom, rotation, blur, viewpoint change, JPEG compression, light change, different rendering styles and multiple structures. We have measured the quality of competing correspondence selection algorithms in terms of four performance metrics -i.e., precision, recall, F-measure and efficiency. Moreover, we propose to combine the strengths of eight competing methods by combining their correspondence selection results. Extensive experimental results are reported to demonstrate the superiority of several fusion strategies to individual methods, which suggests the possibility of adaptively combining those methods for even better performance.

Endoscopic transnasal canaliculorhinostomy for refractory common canalicular obstruction with an unidentifiable lacrimal sac.

AIM: To describe the role of endoscopic transnasal canaliculorhinostomy (ETC) in refractory common canalicular obstruction (CCO) associated with an absent or unidentifiable lacrimal sac. METHODS: The records of patients with refractory CCO who underwent ETC at the Eye Hospital of Wenzhou Medical University from October 2007 to December 2016 were retrospectively reviewed. RESULTS: Fifty-six patients (56 eyes) with refractory CCO were recruited into the study. Eight patients were excluded due to the presence of a residual lacrimal sac or failure to complete the follow-up duration. The anatomic and functional success rates were both 85.4% (41/48) at a mean follow-up of 18.6mo. Five cases failed as a result of ostial synechia and two failed because of ostial obstruction by granulation. Postoperative complications included mild nasal bleeding in 5 cases, dried nasal feeling in 8 cases, and olfactory dysfunction in 4 cases. CONCLUSION: Although being surgically challenging, ETC has comparable findings to its external approach counterpart or conjunctivodacryocystorhinostomy (CDCR) with Jones tube. And it may prove to be a novel alternate surgical technique for patients with refractory CCO without identifiable lacrimal sac.