Review on the Methods of Automatic Liver Segmentation from Abdominal Images

Automatic liver segmentation from abdominal images is challenging on the aspects of segmentation accuracy, automation and robustness. There exist many methods of liver segmentation and ways of categorisingthem. In this paper, we present a new way of summarizing the latest achievements in automatic liver segmentation. We categorise a segmentation method according to the image feature it works on, therefore better summarising the performance of each category and leading to finding an optimal solution for a particular segmentation task. All the methods of liver segmentation are categorized into three main classes including gray level based method, structure based method and texture based method. In each class, the latest advance is reviewed with summary comments on the advantages and drawbacks of each discussed approach. Performance comparisons among the classes are given along with the remarks on the problems existed and possible solutions. In conclusion, we point out that liver segmentation is still an open issue and the tendency is that multiple methods will be employed together to achieve better segmentation performance.

Improvement of Liver Segmentation by Combining High Order Statistical Texture Features with Anatomical Structural Features

Automatic segmentation of liver in medical images is challenging on the aspects of accuracy, automation and robustness. A crucial stage of the liver segmentation is the selection of the image features for the segmentation. This paper presents an accurate liver segmentation algorithm. The approach starts with a texture analysis which results in an optimal set of texture features including high order statistical texture features and anatomical structural features. Then, it creates liver distribution image by classifying the original image pixelwisely using support vector machines. Lastly, it uses a group of morphological operations to locate the liver organ accurately in the image. The novelty of the approach is resided in the fact that the features are so selected that both local and global texture distributions are considered, which is important in liver organ segmentation where neighbouring tissues and organs have similar greyscale distributions. Experiment results of liver segmentation on CT images using the proposed method are presented with performance validation and discussion.

Liver Segmentation from CT Image Using Fuzzy Clustering and Level Set

This paper presents a fully automatic segmentation method of liver CT scans using fuzzy c-mean clustering and level set. First, the contrast of original image is enhanced to make boundaries clearer;second, a spatial fuzzy c-mean clustering combining with anatomical prior knowledge is employed to extract liver region automatically;thirdly, a distance regularized level set is used for refinement;finally, morphological operations are used as post-processing. The experiment result shows that the method can achieve high accuracy (0.9986) and specificity (0.9989). Comparing with standard level set method, our method is more effective in dealing with over-segmentation problem.

Recent advances in chemical protein synthesis:method developments and biological applications

The central dogma of modern biology underscores the pivotal roles proteins play in diverse biological processes,the study of which necessitates advanced methods to produce proteins with precision and versatility.Chemical protein synthesis,a powerful approach utilizing chemical reactions for the de novo construction of structurally accurate proteins,has emerged as a transformative tool for studying proteins and generating protein derivatives/mimics inaccessible by natural biological machinery,including post-translationally modified proteins,proteins comprised of unnatural amino acids,as well as mirror-image proteins.This review summarizes recent strides in synthetic method developments for chemical protein synthesis,including innovative techniques in solid-phase peptide synthesis,the challenges presented by difficult sequences in either synthesis or folding and the exploration of novel ligation reactions using both chemical and enzymatic methods.Furthermore,the review also delves into newly developed protocols for site-selective protein modifications and the generation of stapled or macrocyclized peptides/miniproteins,highlighting the power of chemical methods to make structurally diverse proteins.Recent applications of synthetic proteins in investigating post-translational modifications(phosphorylation,lipidation,glycosylation,ubiquitination,etc.),mirror-image biological processes and drug development are further discussed.Together,these topics provide a comprehensive overview of the current landscape of chemical protein synthesis.

Three modes of a direct-current plasma jet operated underwater to degrade methylene blue

A direct-current air plasma jet operated underwater presents three stable modes including an intermittently-pulsed discharge, a periodically-pulsed discharge and a continuous discharge with increasing the power voltage. The three discharge modes have different appearances for the plasma plumes. Moreover, gap voltage-current characteristics indicate that the continuous discharge is in a normal glow regime. Spectral lines from reactive species（OH, N2, N2^＋, Hα,and O） have been revealed in the emission spectrum of the plasma jet operated underwater.Spectral intensities emitted from OH radical and oxygen atom increase with increasing the power voltage or the gas flow rate, indicating that reactive species are abundant. These reactive species cause the degradation of the methylene blue dye in solution. Effects of the experimental parameters such as the power voltage, the gas flow rate and the treatment time are investigated on the degradation efficiency. Results indicate that the degradation efficiency increases with increasing the power voltage, the gas flow rate or the treatment time. Compared with degradation in the intermittently-pulsed mode or the periodically-pulsed one, it is more efficient in the continuous mode, reaching 98% after 21 min treatment.

Automatic Alzheimer’s Disease Recognition from MRI Data Using Deep Learning Method

Alzheimer’s Disease (AD), the most common form of dementia, is an incurable neurological condition that results in a progressive mental deterioration. Although definitive diagnosis of AD is difficult, in practice, AD diagnosis is largely based on clinical history and neuropsychological data including magnetic resource imaging (MRI). Increasing research has been reported on applying machine learning to AD recognition in recent years. This paper presents our latest contribution to the advance. It describes an automatic AD recognition algorithm that is based on deep learning on 3D brain MRI. The algorithm uses a convolutional neural network (CNN) to fulfil AD recognition. It is unique in that the three dimensional topology of brain is considered as a whole in AD recognition, resulting in an accurate recognition. The CNN used in this study consists of three consecutive groups of processing layers, two fully connected layers and a classification layer. In the structure, every one of the three groups is made up of three layers, including a convolutional layer, a pooling layer and a normalization layer. The algorithm was trained and tested using the MRI data from Alzheimer’s Disease Neuroimaging Initiative. The data used include the MRI scanning of about 47 AD patients and 34 normal controls. The experiment had shown that the proposed algorithm delivered a high AD recognition accuracy with a sensitivity of 1 and a specificity of 0.93.

Acoustic emissions evaluation of the dynamic splitting tensile properties of steel fiber reinforced concrete under freeze-thaw cycling

This study empirically investigated the influence of freeze-thaw cycling on the dynamic splitting tensile properties of steel fiber reinforced concrete(SFRC).Brazilian disc splitting tests were conducted using four loading rates(0.002,0.02,0.2,and 2 mm/s)on specimens with four steel fiber contents(0%,0.6%,1.2%,and 1.8%)subjected to 0 and 50 freeze-thaw cycles.The dynamic splitting tensile damage characteristics were evaluated using acoustic emission(AE)parameter analysis and Fourier transform spectral analysis.The results quantified using the freeze-thaw damage factor defined in this paper indicate that the degree of damage to SFRC caused by freeze-thaw cycling was aggravated with increasing loading rate but mitigated by increasing fiber content.The percentage of low-frequency AE signals produced by the SFRC specimens during loading decreased with increasing loading rate,whereas that of high-frequency AE signals increased.Freeze-thaw action had little effect on the crack types observed during the early and middle stages of the loading process;however,the primary crack type observed during the later stage of loading changed from shear to tensile after the SFRC specimens were subjected to freeze-thaw cycling.Notably,the results of this study indicate that the freeze-thaw damage to SFRC reduces AE signal activity at low frequencies.

Studies on 2-Formylphenylboronic Acid-Based Ser/Thr Ligation and Cys/Pen Ligation

Main observation and conclusion Developing an effective chemoselective ligation strategy for assembling unprotected peptide segments is important to peptide/protein synthesis.The ligation efficiency and selectivity depend on the chemistry between the C-terminal active ester of the peptide(e.g.,the thioester in Native Chemical Ligation or the salicylaldehyde ester in Ser/Thr Ligation and Cys/Pen Ligation)and N-terminal functional groups of the second peptide(Cys or Ser/Thr).Increasing the reactivity of the ligation and decreasing the hydrolysis of the active ester are more like the opposite sites in balance.We investigated the potential application of the peptide acyl ester of 2-formylphenylboronic acid(2-FPBA)in the Ser/Thr ligation and Cys/Pen ligation.With the assistance of boronic acid group,the peptidyl FPBA ester showed remarkable stability in aqueous buffer and its reactivity towards Ser/Thr and Cys/Pen also improved.However,the strong coordination of the amine at the N-terminus and boronic acid suppressed the acyl transfer process when the peptide acyl group was used.More effects should be made to enhance the ligation chemistry.

Development of aspartic acid ligation for peptide cyclization derived from serine/threonine ligation

Based on a mechanism analogous to the serine/threonine ligation, the aspartic acid ligation, which is facilitated by the γ-amino alcohol based ligation and oxidation, is developed and applied to the synthesis of cyclic peptides. The γ-hydroxyl group triggers the ring-chain tautomerization via a 6-endo-trig process,while the δ-hydroxyl group facilitates the oxidative cleavage of the vicinal diol to give carboxylic acid.

Establishing the structure-activity relationship of teixobactin

In 2015,a new antimicrobial peptide agent was discovered,termed teixobactin.Over the past few years,the structure-activity relationship of teixobactin has been extensively studied.Here,the updated studies have been summarized to provide structure-activity relationship established to date.It can be seen that position 1,2,5 and 6 of teixobactin are not tolerant of diversion from the native amino acids.In positions 7 and 11,native amino acids give the highest activity but there is tolerance for other amino acids.Positions 3,4,9 and 10 are very tolerant of substitution while maintaining good potency and a broad activity spectrum.Activity does not depend on absolute stereochemistry,but on the relative stereochemistry and positions 1,4,5,and 8 must contain D-amino acids.The ring and tail structure are necessary for activity,macrolactone and lactam rings are both acceptable.Some teixobactin analogues show greater activity than native teixobactin.All conducted animal studies show positive results with no animal deaths.

A double‐mode planar argon plume produced by varying the distance from an atmospheric pressure plasma jet

Atmospheric pressure planar plumes are desirable for the applications of low temperature plasmas,such as rapid modification of large‐scale surfaces.Up to now,only single‐mode planar plumes with either a streamer mode or a filamentary mode have been reported in the literature.Distinctive from the single‐mode planar plumes,a double‐mode argon planar plume has been generated in this article,which operates in the streamer mode with a larger distance away from a plasma jet and transits to the filamentary mode with decreasing the distance.Discharge characteristics and plasma parameters are compared for the two modes.Results indicate that the streamer mode and the filamentary mode correspond to pulsed and humped discharges respectively.Fast photography reveals that the streamer‐mode plume is composed of stochastically branching streamers,while the filamentary‐mode plume results from a series of moving filaments similar to those in barrier discharge.In contrast to the streamer mode,the filamentary mode has lower excited electron temperature and vibrational temperature,whereas higher electron density and gas temperature.In addition,better hydrophilicity of polyethylene terephthalate surface is achieved in the filamentary mode.

Chemical synthesis of glycoproteins

Recently,there has been an overwhelming demand for studies on protein post-translational modification(PTM)to understand the increasing complexity from the level of the genome to the proteome.The covalent modifications of proteins with phosphates,lipids,sugars or other residues confer on these proteins additional structural and functional diversity.For instance,protein phosphorylation is involved in a wide range

Professor Henry N.C. Wong, extraordinary synthetic chemist and great mentor

Professor Henry N.C.Wong obtained his B.Sc.degree with First Class Honours from The Chinese University of Hong Kong(CUHK)in 1973 and his Ph.D.degree from University College London(with Professor Franz Sondheimer)in 1976.After working at Harvard University as a Postdoctoral Associate with Professor Robert B.Woodward,he returned to University College London to begin his independent research undertaking as Ramsay Memorial Fellow.From 1980 to 1982,Professor Wong did research at Shanghai Inst让ute of Organic Chemistry,The Chinese Academy of Sciences.In 1982,he went back to Hong Kong,and started his career at CUHK his alma mater.He retired in 2018,and is now Emeritus Professor of Chemistry and Research Profess or.

15^(th) Chinese International Peptide Symposium

As one of the most important and influential peptide conferences in the world,Chinese International Peptide Symposium(CPS)was founded in 1990 and has been held every two years for14 consecutive sessions.From July 4thto 6th,2018,the 15th CPS will be held in Shenzhen and hosted by Tsinghua University.This conference will focus on the topics of"Peptide:Technological Innovation and a Better Life",covering the synthesis,structure and function of peptides and proteins,peptide-based drug discovery,