Deep learning framework for three-dimensional surface reconstruction of object of interest in photoacoustic tomography.

Photoacoustic tomography (PAT) is a non-ionizing hybrid imaging technology of clinical importance that combines the high contrast of optical imaging with the high penetration of ultrasonic imaging. Two-dimensional (2D) tomographic images can only provide the cross-sectional structure of the imaging target rather than its overall spatial morphology. This work proposes a deep learning framework for reconstructing three-dimensional (3D) surface of an object of interest from a series of 2D images. It achieves end-to-end mapping from a series of 2D images to a 3D image, visually displaying the overall morphology of the object. The framework consists of four modules: segmentation module, point cloud generation module, point cloud completion module, and mesh conversion module, which respectively implement the tasks of segmenting a region of interest, generating a sparse point cloud, completing sparse point cloud and reconstructing 3D surface. The network model is trained on simulation data sets and verified on simulation, phantom, and in vivo data sets. The results showed superior 3D reconstruction performance both visually and on the basis of quantitative evaluation metrics compared to the state-of-the-art non-learning and learning approaches. This method potentially enables high-precision 3D surface reconstruction from the tomographic images output by the preclinical PAT system without changing the imaging system. It provides a general deep learning scheme for 3D reconstruction from tomographic scanning data.

QOCT-Net: A Physics-Informed Neural Network for Intravascular Optical Coherence Tomography Attenuation Imaging.

Intravascular optical coherence tomography (IVOCT) provides high-resolution, depth-resolved images of coronary arterial microstructure by acquiring backscattered light. Quantitative attenuation imaging is important for accurate characterization of tissue components and identification of vulnerable plaques. In this work, we proposed a deep learning method for IVOCT attenuation imaging based on the multiple scattering model of light transport. A physics-informed deep network named Quantitative OCT Network (QOCT-Net) was designed to recover pixel-level optical attenuation coefficients directly from standard IVOCT B-scan images. The network was trained and tested on simulation and in vivo datasets. Results showed superior attenuation coefficient estimates both visually and based on quantitative image metrics. The structural similarity, energy error depth and peak signal-to-noise ratio are improved by at least 7%, 5% and 12.4%, respectively, compared with the state-of-the-art non-learning methods. This method potentially enables high-precision quantitative imaging for tissue characterization and vulnerable plaque identification.

Quantitative photoacoustic tomography with light fluence compensation based on radiance Monte Carlo model.

Objective. Photoacoustic tomography (PAT) is a rapidly evolving imaging modality that provides images with high contrast and spatial resolution showing the optical properties of biological tissues. The photoacoustic pressure is proportional to the product of the optical absorption coefficient and the local light fluence. The essential challenge in reconstructing quantitative images representing spatially varying absorption coefficients is the unknown light fluence. In addition, optical attenuation induces spatial variations in the light fluence, and the heterogeneity of the fluence determines the limits of reconstruction quality and depth.Approach.In this work, a reconstruction enhancement scheme is proposed to compensate for the variation in the light fluence in the absorption coefficient recovery. The inverse problem of the radiance Monte Carlo model describing light transport through the tissue is solved by using an alternating optimization strategy. In the iteration, the absorption coefficients and photon weights are alternately updated.Main results.The method provides highly accurate quantitative images of absorption coefficients in simulations, phantoms, andin vivostudies. The results show that the method has great potential for improving the accuracy of absorption coefficient recovery compared to conventional reconstruction methods that ignore light fluence variations. Comparison with state-of-the-art fluence compensation methods shows significant improvements in root mean square error, normalized mean square absolute distance, and structural similarity metrics.Significance.This method achieves high precision quantitative imaging by compensating for nonuniform light fluence without increasing the complexity and operation of the imaging system.

A Deep Learning Method for Motion Artifact Correction in Intravascular Photoacoustic Image Sequence.

In vivo application of intravascular photoacoustic (IVPA) imaging for coronary arteries is hampered by motion artifacts associated with the cardiac cycle. Gating is a common strategy to mitigate motion artifacts. However, a large amount of diagnostically valuable information might be lost due to one frame per cycle. In this work, we present a deep learning-based method for directly correcting motion artifacts in non-gated IVPA pullback sequences. The raw signal frames are classified into dynamic and static frames by clustering. Then, a neural network named Motion Artifact Correction (MAC)-Net is designed to correct motion in dynamic frames. Given the lack of the ground truth information on the underlying dynamics of coronary arteries, we trained and tested the network using a computer-generated dataset. Based on the results, it has been observed that the trained network can directly correct motion in successive frames while preserving the original structures without discarding any frames. The improvement in the visual effect of the longitudinal view has been demonstrated based on quantitative evaluation of the inter-frame dissimilarity. The comparison results validated the motion-suppression ability of our method comparable to gating and image registration-based non-learning methods, while maintaining the integrity of the pullbacks without image preprocessing. Experimental results from in vivo intravascular ultrasound and optical coherence tomography pullbacks validated the feasibility of our method in the in vivo intracoronary imaging scenario.

Effects of zhongfeng cutong moxibustion on motor function and corticospinal tract in the patients with motor dysfunction during the recovery period of cerebral infarction / 中国针灸

OBJECTIVES@#To observe the effects of zhongfeng cutong moxibustion (moxibustion therapy for unblocking and treating stroke) on the motor function and the structure of corticospinal tract (CST) in the patients with motor dysfunction during the recovery period of cerebral infarction, and to explore the central mechanism of this moxibustion therapy for improving the motor function.@*METHODS@#Fifty patients with motor dysfunction during the recovery period of cerebral infarction were randomly divided into an observation group (25 cases, 1 case dropped out) and a control group (25 cases, 1 case dropped out). The patients in both groups underwent the conventional basic treatment. In the control group, acupuncture was applied to Baihui (GV 20) and Shuigou (GV 26), as well as Chize (LU 5), Neiguan (PC 6), Weizhong (BL 40) and Sanyinjiao (SP 6) etc. on the affected side. Besides the intervention of the control group, in the observation group, zhongfeng cutong moxibustion therapy was combined at Baihui (GV 20), Shenque (CV 8) and bilateral Zusanli (ST 36). Both acupuncture and moxibustion therapies were delivered once daily, 5 times a week, for 2 weeks. The scores of Fugl-Meyer assessment scale (FMA) and National Institutes of Health stroke scale (NIHSS) were compared between the two groups before and after treatment. The diffusion tensor imaging technique was used to observe the fractional anisotropy (FA) of CST at the bilateral whole segment, the cerebral cortex, the posterior limb of the internal capsule and the cerebral peduncle before and after treatment in the two groups.@*RESULTS@#The scores of the upper and the lower limbs of FMA, as well as the total FMA score swere increased after treatment when compared with those before treatment in the two groups (P<0.05), the upper limb FMA score and the total FMA score in the observation group were higher than those in the control group (P<0.05), and NIHSS scores of the two groups were dropped compared with those before treatment (P<0.01). FA of CST at the bilateral sides of the posterior limb of the internal capsule and the whole segment on the focal side was improved in comparison with that before treatment in the observation group (P<0.05), and FA of CST at the healthy side of the whole segment was higher than that before treatment in the control group (P<0.05).@*CONCLUSIONS@#Zhongfeng cutong moxibustion improves motor function and reduces neurological deficits in the patients with motor dysfunction during the recovery period of cerebral infarction, which may be related to enhancing the remodeling of white matter fiber bundles in the corticospinal tract on the focal side of the whole segment and the bilateral posterior limb of the internal capsule.

Circadian rhythm and health: dialogue between traditional Chinese medicine and modern medicine / 中国中药杂志

Circadian rhythm refers to the daily rhythmic variations in an organism. The irregular lifestyles of modern humans have led to a high incidence of chronic diseases, highlighting an inseparable relationship between disrupted circadian rhythm and disease development. TCM has long discussed rhythmic variations, with records dating back to the Yellow Emperor's Inner Canon(Huang Di Nei Jing), which laid a rich theoretical foundation for the research on circadian rhythm. Modern medical research has provided a more comprehensive explanation of its molecular mechanisms. This article integrated the current understanding of circadian rhythm in both Chinese and western medicine, emphasizing the crucial relationship between rhythm regulation and disease treatment. By highlighting the interdisciplinary nature of the two fields, it offers new directions for exploring the field of chronomedicine.

Research progress on image-based calculation of coronary artery fractional flow reserve / 生物医学工程学杂志

Coronary artery fractional flow reserve (FFR) is a critical physiological indicator for assessment of impaired blood flow caused by coronary artery stenosis. The wire-based invasive measurement of blood flow pressure gradient across stenosis is the gold standard for clinical measurement of FFR. However, it has the risk of vascular injury and requires the use of vasodilators, increasing the time and overall cost of interventional examination. Coronary imaging is playing an important role in clinical diagnosis of stenotic lesions, evaluation of severity of lesions, and planning of therapies. In recent years, the computation of FFR based on the physiological information of blood flow obtained from routinely collected coronary image data has become a research focus in this field. This technique reduces the cost of physiological assessment of coronary lesions and the use of pressure wires. It is beneficial to strengthen the physiological guidance in interventional therapy. In order to better understand this emerging technique, this paper highlights its implementation principle and diagnostic performance, analyzes practical problems and current challenges in clinical applications, and discusses possible future development.

Astragali Radix-Curcumae Rhizoma combination inhibits proliferation, migration, and invasion of colon cancer HT-29 cells by regulating EMT / 中国中药杂志

This study aims to investigate the effect of Astragali Radix-Curcumae Rhizoma(AC) combination on the proliferation, migration, and invasion of colon cancer HT-29 cells based on epithelial-mesenchymal transition(EMT). HT-29 cells were respectively treated with 0, 3, 6 and 12 g·kg~(-1) AC-containing serum for 48 h. The survival and growth of cells were measured by thiazole blue(MTT) colorimetry, and the proliferation, migration, and invasion of cells were detected by 5-ethynyl-2'-deoxyuridine(EdU) test and Transwell assay. Cell apoptosis was examined by flow cytometry. The BALB/c nude mouse model of subcutaneous colon cancer xenograft was established, and then model mice were classified into blank control group, 6 g·kg~(-1) AC group, and 12 g·kg~(-1) AC group. The tumor weight and volume of mice were recorded, and the histopathological morphology of the tumor was observed based on hematoxylin-eosin(HE) staining. The expression of apoptosis-associated proteins B-cell lymphoma-2-associated X protein(Bax), cysteine-aspartic acid protease-3(caspase-3), and cleaved caspase-3, and EMT-associated proteins E-cadherin, MMP9, MMP2 and vimentin in HT-29 cells and mouse tumor tissues after the treatment of AC was determined by Western blot. The results showed that cell survival rate and the number of cells at proliferation stage decreased compared with those in the blank control group. The number of migrating and invading cells reduced and the number of apoptotic cells increased in the administration groups compared with those in the blank control group. As for the in vivo experiment, compared with the blank control group, the administration groups had small tumors with low mass and shrinkage of cells and karyopycnosis in the tumor tissue, indicating that the AC combination may improve EMT. In addition, the expression of Bcl2 and E-cadherin increased and the expression of Bax, caspase-3, cleaved caspase-3, MMP9, MMP2, and vimentin decreased in HT-29 cells and tumor tissues in each administration group. In summary, the AC combination can significantly inhibit the proliferation, invasion, migration, and EMT of HT-29 cells in vivo and in vitro and promote the apoptosis of colon cancer cells.

Quantitative endoscopic photoacoustic tomography using a convolutional neural network.

Endoscopic photoacoustic tomography (EPAT) is a catheter-based hybrid imaging modality capable of providing structural and functional information of biological luminal structures, such as coronary arterial vessels and the digestive tract. The recovery of the optical properties of the imaged tissue from acoustic measurements achieved by optical inversion is essential for implementing quantitative EPAT (qEPAT). In this paper, a convolutional neural network (CNN) based on deep gradient descent is developed for qEPAT. The network enables the reconstruction of images representing the spatially varying absorption coefficient in cross-sections of the tubular structures from limited measurement data. The forward operator reflecting the mapping from the absorption coefficient to the optical deposition due to pulsed irradiation is embedded into the network training. The network parameters are optimized layer by layer through the deep gradient descent mechanism using the numerically simulated data. The operation processes of the forward operator and its adjoint operator are separated from the network training. The trained network outputs an image representing the distribution of absorption coefficients by inputting an image that represents the optical deposition. The method has been tested with computer-generated phantoms mimicking coronary arterial vessels containing various tissue types. Results suggest that the structural similarity of the images reconstructed by our method is increased by about 10% in comparison with the non-learning method based on error minimization in the case of the same measuring view.

Development, reliability and validity of the cultural competency assessment scale for geriatric nurse specialists / 中国实用护理杂志

Objective:To develop a cultural competency assessment scale for geriatric clinical nurse specialists and test its reliability and validity.Methods:Through literature research, qualitative interviews, expert correspondence, and pretesting, the cultural competency assessment scale for geriatric clinical nurse specialists was developed. A total of 140 geriatric nurses from 8 tertiary hospitals in Beijing, Guizhou, Harbin, Shandong and Shaanxi from July to September 2021 were selected for the survey.Results:The final cultural competency assessment scale for geriatric clinical nurse specialists consisted of 4 dimensions of cultural knowledge, cultural awareness, cultural skills, and cultural interaction behaviors, with 31 entries, Cronbach α coefficient of 0.953 for the scale, Cronbach α coefficient of 0.875-0.974 for the 4 dimensions, and retest reliability of 0.925. I-CVI was 0.857-1.000, and the average S-CVI was 0.974. The cumulative contribution of the four common factors was 72.51%. Conclusions:The reliability and validity of the cultural competency assessment scale for geriatric clinical nurse specialists are good and can be used to evaluate the cultural competency of geriatric clinical nurse specialists.

Effect of Tiaoshen acupuncture on anxiety after methamphetamine withdrawal / 中国针灸

OBJECTIVE@#To compare the therapeutic effect between Tiaoshen acupuncture combined with psychotherapy and simple psychotherapy on anxiety after methamphetamine withdrawal.@*METHODS@#A total of 78 patients were randomized into an observation group (39 cases, 2 cases dropped off) and a control group (39 cases, 1 case dropped off). Psychotherapy was given in the control group. On the basis of the treatment in the control group, Tiaoshen acupuncture was applied at Baihui (GV 20), Shenting (GV 24), Benshen (GB 13), Neiguan (PC 6) and Shenmen (HT 7) in the observation group. The treatment was given once a day, 6 days were as one course and totally 4 courses were required in both groups. The scores of Hamilton anxiety scale (HAMA), quality of life for drug addicts (QOL-DA) and Pittsburgh sleep quality index (PSQI) before and after treatment were observed in both groups.@*RESULTS@#After treatment, the various scores and the total scores of HAMA, QOL-DA and PSQI were decreased compared before treatment in both groups (P<0.05), and the scores of somatic anxiety factor, the psychic anxiety factor and the total score of HAMA, each various score and the total score of QOL-DA as well as the scores of sleep quality, time to fall asleep, sleep time, daytime dysfunction and the total score of PSQI in the observation group were lower than those in the control group (P<0.05).@*CONCLUSION@#Tiaoshen acupuncture combined with psychotherapy can relieve the anxiety in patients with anxiety after methamphetamine withdrawal, improve the quality of life and sleep, the therapeutic effect is superior to the simple psychotherapy.

Clinical observation of Tiaoshen acpuncture for dry eye syndrome with yin deficiency of liver and kidney / 中国针灸

OBJECTIVE@#To compare the curative effect of Tiaoshen acupuncture combined with artificial tears and artificial tears alone for dry eye syndrome with yin deficiency of liver and kidney.@*METHODS@#A total of 70 patients of dry eye syndrome with yin deficiency of liver and kidney were randomized into an acupuncture combined with medication group (35 cases, 2 cases dropped off) and a medication group (35 cases, 3 cases dropped off). In the medication group, 0.1% sodium hyaluronate eye drop was applied, 3 times a day, 1 drop each time. On the basis of the treatment as the medication group, Tiaoshen acupuncture was applied at Shenting (GV 24), Shenmen (HT 7), Benshen (GB 13), Taixi (KI 3), Taichong (LR 3), Guangming (GB 37), Fengchi (GB 20), Tongziliao (GB 1), Yuyao (EX-HN 4) in the acupuncture combined with medication group, Tongziliao (GB 1) and Yuyao (EX-HN 4) were connect with electroacupuncture, the needles were retained for 30 min, once a day, 6 times a week. Both groups were treated for 2 weeks. Before and after treatment, the clinical symptom score, SchirmerⅠtest (SⅠT), break-up time (BUT), corneal fluorescein staining (FL) score and Hamilton anxiety scale (HAMA) score were observed in the two groups, and the clinical efficacy was compared in the two groups.@*RESULTS@#Compared before treatment, the clinical symptom scores, corneal FL and HAMA scores were decreased (P<0.05), the levels of SⅠT and BUT were increased after treatment in the two groups (P<0.05). After the treatment, the clinical symptom score, FL and HAMA scores in the acupuncture combined with medication group were lower than the medication group (P<0.05), the levels of SⅠT and BUT in the acupuncture combined with medication group were higher than the medication group (P<0.05). The total effective rate in the acupuncture combined with medication group was 90.9% (30/33), which was higher than 71.9% (23/32) in the medication group (P<0.05).@*CONCLUSION@#Tiaoshen acupuncture combined with artificial tears could promote the secretion of tears for patients of dry eye syndrome with yin deficiency of liver and kidney, repair corneal defect and prolong tear film break-up time, and alleviate anxiety state, its curative effect is better than simple artificial tears.

SUN's abdominal acupuncture for depression after methamphetamine withdrawal: a randomized controlled trial / 中国针灸

OBJECTIVE@#To compare the clinical effect of SUN 's abdominal acupuncture and conventional acupuncture in the treatment of depression after methamphetamine withdrawal.@*METHODS@#A total of 80 female patients with depression after methamphetamine withdrawal were randomly divided into an observation group (40 cases, 1 case dropped off) and a control group (40 cases, 2 cases dropped off). The control group was treated with conventional acupuncture at Baihui (GV 20), Yintang (GV 29), Taichong (LR 3), Shenmen (HT 7), Neiguan (PC 6), Danzhong (GV 17), and the observation group was treated with SUN 's abdominal acupuncture at area 1 of the abdomen and area 8 of the abdomen. Both groups were treated once a day, 30 min each time, 6 days as a course of treatment, 1 day rest between treatment courses, a total of 4 courses of treatment. The scores of withdrawal symptoms, Hamilton depression scale (HAMD), Pittsburgh sleep quality index (PSQI) scale and serum serotonin (5-HT) level were compared between the two groups before and after treatment.@*RESULTS@#After treatment, the scores of withdrawal symptoms, HAMD and the various scores and total score of PSQI scale in the two groups were all lower than before treatment (P<0.01), and the scores of withdrawal symptoms, HAMD and the sleep quality, time to fall asleep, sleep time scores and total score of PSQI in the observation group were lower than the control group (P<0.05, P<0.01). After treatment, the serum 5-HT level of the two groups was increased (P<0.01), and that in the observation group was higher than the control group (P<0.05).@*CONCLUSION@#SUN 's abdominal acupuncture can improve withdrawal symptom, depression and sleep quality, increase serum 5-HT content in treatment of depression after methamphetamine withdrawal, and has better effect than conventional acupuncture.

Method for parametric imaging of attenuation by intravascular optical coherence tomography.

Catheter-based intravascular optical coherence tomography (IVOCT) is a powerful imaging modality for visualization of atherosclerosis with high resolution. Quantitative characterization of various tissue types by attenuation coefficient (AC) extraction has been proven to be a potentially significant application of OCT attenuation imaging. However, existing methods for AC extraction from OCT suffer from the challenge of variability in complex tissue types in IVOCT pullback data such as healthy vessel wall, mixed atherosclerotic plaques, plaques with a single component and stent struts, etc. This challenge leads to the ineffectiveness in the tissue differentiation by AC representation based on single scattering model of OCT signal. In this paper, we propose a novel method based on multiple scattering model for parametric imaging of optical attenuation by AC retrieval from IVOCT images conventionally acquired during cardiac catheterization. The OCT signal characterized by the AC is physically modeled by Monte Carlo simulation. Then, the pixel-wise AC retrieval is achieved by iteratively minimizing an error function regarding the modeled and measured backscattered signal. This method provides a general scheme for AC extraction from IVOCT without the premise of complete attenuation of the incident light through the imaging depths. Results of computer-simulated and clinical images demonstrate that the method can avoid overestimation at the end of the depth profile in comparison with the approaches based on the depth-resolved (DR) model. The energy error depth and structural similarity are improved by about 30% and 10% respectively compared with DR. It provides a useful way to differentiate and characterize arterial tissue types in IVOCT images.

Role of Magnetic Resonance Imaging in Predicting Residual Breast Cancer After Vacuum-Assisted Breast Biopsy.

PURPOSE: This study aims to evaluate the effectiveness of breast magnetic resonance imaging (MRI) in detecting residual breast cancer in patients after vacuum-assisted breast biopsy (VABB). METHODS: Between 2012 and 2019, 26 patients with breast cancer who underwent VABB were enrolled. Breast MRI was conducted after VABB. Imaging findings were then compared with the histopathological results. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated. RESULTS: Residual cancer was confirmed histologically in 8 of the 26 patients after VABB. The overall sensitivity, specificity, PPV, NPV, and accuracy of MRI for diagnosing residual cancer were 79.9%, 73.0%, 87.1%, 61.3%, and 77.8%, respectively. The sensitivity and NPV improved to 100%, when the number of biopsy specimens was larger than five. CONCLUSION: Breast MRI showed high sensitivity and NPV in detecting residual breast tumor after VABB.

Progress of motion artifact correction in photoacoustic microscopy and photoacoustic tomography / 生物医学工程学杂志

Photoacoustic imaging (PAI) is a rapidly developing hybrid biomedical imaging technology, which is capable of providing structural and functional information of biological tissues. Due to inevitable motion of the imaging object, such as respiration, heartbeat or eye rotation, motion artifacts are observed in the reconstructed images, which reduce the imaging resolution and increase the difficulty of obtaining high-quality images. This paper summarizes current methods for correcting and compensating motion artifacts in photoacoustic microscopy (PAM) and photoacoustic tomography (PAT), discusses their advantages and limits and forecasts possible future work.

SWOT analysis and promotion strategy of core employment competence of master of nursing specialist in China / 中国实用护理杂志

Objective:To explore the internal and external factors that affect the core competitiveness of nursing degree graduates in China, and to put forward strategies for improvement.Methods:SWOT analysis method was used to analyze the strengths, weaknesses, external opportunities and threats of the core competitiveness of nursing graduates.Results:Students' own advantages include strong self-learning ability, strong scientific research thinking ability, strong education communication ability; disadvantages include inaccurate professional positioning, lack of clinical experience and professional quality; external opportunities include national policy attention, clinical platform demand, high attention of colleges and universities; threat factors include backward construction of teaching staff, lack of assessment methods and evaluation system, and lack of specialized curriculum system Characteristics of science and technology.Conclusion:The factors that affect the promotion of core competitiveness of professional degree nursing graduates in China cover two aspects: students themselves and training colleges and universities. We should make corresponding coping strategies on the basis of overall consideration of strengths and weaknesses, opportunities and challenges.

Practical analysis of hemostatic compression after high pressure injection of magnetic resonance contrast in patients with acute cerebral infarction / 中国实用护理杂志

Objective:In the research, the traditional mercury sphygmomanometer was used to press the puncture point to evaluate the hemostatic effect.Methods:Eighty patients with acute cerebral infarction diagnosed clinically in Xuanwu Hospital of Capital Medical University from June 2018 to December 2019 were examined by magnetic resonance perfusion examination. The serial number of the patient was randomly divided into the group by random digital table, and the puncture point was pressed by mercury sphygmomanometer after needle extraction in the auxiliary pressing group, and the individual systolic blood pressure intensity was set as the pressing intensity, while the control group adopted independent vertical pressing technique. After examination, the puncture points of the two groups were qualitatively evaluated, such as secondary bleeding, hematoma, ecchymosis, normal and so on.Results:In the auxiliary compression group, there were 3 cases of secondary hemorrhage, 1 case of hematoma, 0 cases of ecchymosis and 36 cases of normal, while in the control group, there were 4 cases of bleeding, 2 case of hematoma, 1 case of ecchymosis and 33 cases of normal ( χ2value was 4.372-34.225, P<0.05). Conclusion:Traditional mercury sphygmomanometer-assisted pressing puncture point can make personalized nursing hemostasis plan for patients with acute cerebral infarction, reduce the phenomenon of puncture point bleeding, ecchymosis, and even subcutaneous hematoma caused by unstable pressing and unequal force, and practice high-quality nursing service.

Isolation, identification and prokaryotic expression of a bacteriocin-like substance from Bacillus licheniformis / 生物工程学报

The ban on addition of antibiotics in animal feed in China has made the search for new antibiotics substitutes, e.g. bacteriocin, a hot topic in research. The present study successfully isolated an antibacterial substance producing strain of Bacillus sp. from alpaca feces by agar diffusion method, using Escherichia coli, Salmonella enterica, Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus luteus and Listeria monocytogenes as indicator bacteria. The isolated strain was named as B. licheniformis SXAU06 based on colony morphology, Gram staining and 16S rRNA gene sequence. The antibacterial substance was isolated and purified through a series of procedures including (NH4)2SO4 precipitation, chloroform extraction, molecular interception and SDS-PAGE analysis. Bioinformatics analysis of the LC-MS/MS data indicated that the antibacterial substance was a bacteriocin-like substance (BLIS) with an approximate molecular weight of 14 kDa, and it was designated as BLIS_SXAU06. BLIS_SXAU06 exhibited high resistance to treatment of proteinase K, high temperature, high acidity and alkalinity. BLIS_SXAU06 was heterologously expressed in E. coli and the recombinant BLIS_SXAU06 exhibited effective antibacterial activity against S. aureus, S. epidermidis, M. luteus, and L. monocytogenes, showing potential to be investigated further.

Image reconstruction based on compressed sensing for sparse-data endoscopic photoacoustic tomography.

Endoscopic photoacoustic tomography (EPAT) is an interventional application of photoacoustic tomography (PAT) to visualize anatomical features and functional components of biological cavity structures such as nasal cavity, digestive tract or coronary arterial vessels. One of the main challenges in clinical applicability of EPAT is the incomplete acoustic measurements due to the limited detectors or the limited-view acoustic detection enclosed in the cavity. In this case, conventional image reconstruction methodologies suffer from significantly degraded image quality. This work introduces a compressed-sensing (CS)-based method to reconstruct a high-quality image that represents the initial pressure distribution on a luminal cross-section from incomplete discrete acoustic measurements. The method constructs and trains a complete dictionary for the sparse representation of the photoacoustically-induced acoustic measurements. The sparse representation of the complete acoustic signals is then optimally obtained based on the sparse measurements and a sensing matrix. The complete acoustic signals are recovered from the sparse representation by inverse sparse transformation. The image of the initial pressure distribution is finally reconstructed from the recovered complete signals by using the time reversal (TR) algorithm. It was shown with numerical experiments that high-quality images with reduced under-sampling artifacts can be reconstructed from sparse measurements. The comparison results suggest that the proposed method outperforms the standard TR reconstruction by 40% in terms of the structural similarity of the reconstructed images.