Plug-and-play positioning error compensation model for ripple suppressing in industrial robot polishing

The industrial robot-based polisher has wide applications in the field of optical manufacturing due to the advantages of low cost, high degrees of freedom, and high dynamic performance. However, the large positioning error of the industrial robot can lead to surface ripple and seriously restrict the system performance, but this error can only be inefficiently compensated for by measurement before each processing at present. To address this problem, we discovered the period-phase evolution law of the positioning error and established a double sine function compensation model. In the self-developed robotic polishing platform, the results show that the Z-axis error in the whole workspace after compensation can be reduced to ±0.06m m, which reaches the robot repetitive positioning error level; the Spearman correlation coefficients between the measurement and modeling errors are all above 0.88. In the practical polishing experiments, for both figuring and uniform polishing, the ripple error introduced by the positioning error is significantly suppressed by the proposed model under different conditions. Besides, the power spectral density (PSD) analysis has shown a significant suppression in the corresponding frequency error. This model gives an efficient plug-and-play compensation model for the robotic polisher, which provides possibilities for further improving robotic processing accuracy and efficiency.

Retroperitoneal abscess as a presentation of colon cancer: The largest case set analysis to date, which extracted from our unit and the literature

Objective

Colon cancer with retroperitoneal abscess is a rare and easily misdiagnosed disease and has only been reported via case. There is an urgent need to conduct a dataset analysis for such patients, which is crucial to improving the survival rate and quality of life of these patients.

Methods

Patients with colon cancer associated with retroperitoneal abscess were extracted from our hospital and the PubMed, EMBASE and Web of Science databases. Clinical information, including the patients' basic characteristics, clinical symptoms, laboratory tests, imaging examinations, treatment methods and prognosis was analyzed.

Results

Sixty-one patients were analyzed, with an average age of 65 years. The proportions of right and left colon cancers were 63.9% and 36.1%, respectively. A total of 98.0% of the patients had adenocarcinoma. Many patients have insidious symptoms such as fever and weight loss. At the first medical visit, pain was the most common symptom (71%), with pain in the thigh (21.8%), abdomen (21.8%), and waist and back (14.5%) ranking among the top three. The misdiagnosis rate of the patients referred to our department was 75%, while the overall misdiagnosis rate in the literature was 43.9%. Laboratory tests show that these patients often have elevated white blood cells and anemia. CT examination showed that 87.2% of patients had an iliopsoas muscle abscess, and tumors were not simultaneously detected in 37.2%. A total of 33.9% of patients had local abscesses of the iliopsoas muscle, 26.4% had drainage into the subcutaneous tissue of the waist and upper buttocks, and 22.6% had drainage around the adductor muscle group of the thigh. These patients have a variety of treatments, and many patients have undergone multiple and unnecessary treatments. Thirteen patients died after surgery, and 6 died in the hospital, of whom four were patients undergoing direct surgery, and the other 7 died after discharge due to cachexia.

Conclusion

Colorectal cancer with retroperitoneal abscess is a relatively rare and easily misdiagnosed subtype of colon cancer. It is more likely to occur in right-sided colon adenocarcinoma. The main clinical symptom is pain caused by the drainage of pus to the corresponding areas of the waist, abdomen, and legs. CT is the preferred diagnostic method. Actively treating the abscess and then transitioning to standard colon cancer treatment can prevent patient death and improve treatment quality.

Theoretical and experimental investigations in thermo-mechanical properties of fused silica with pulsed CO2 laser ablation

Laser ablation is widely used as a flexible and non-contact processing technology for the fabrication of fused silica. However, the introduction of thermal stress inevitably leads to crack growth and reduces the lifetime of fused silica. Due to the complicated coupling interaction and properties of fused silica, the unclear thermal stress formation is the bottleneck restricting further development of laser ablation. In this article, a three-dimensional multi-physics thermo-mechanical model was developed to reveal the evolution mechanism, and experiments were performed to validate the simulated results. The surface morphology evolution was elaborated during process cycles, with recoil pressure identified as the key factor in determining surface morphology. Moreover, thermal stress was quantified utilizing optical retardance and stress birefringence, effectively distinguishing between non-thermal and thermal stress induced by laser ablation. The theoretical simulations fit well with experimental measurements. Meanwhile, stress distribution and evolution behaviors were revealed under different processing parameters by this model. This work not only contributes to a profound understanding of the laser ablation process but also establishes a theoretical foundation for achieving high surface quality and non-thermal stress laser ablation.

Densi-melting effect for ultra-precision laser beam figuring with clustered overlapping technology at full-spatial-frequency

Laser beam figuring (LBF), as a processing technology for ultra-precision figuring, is expected to be a key technology for further improving optics performance. To the best of our knowledge, we firstly demonstrated CO₂ LBF for full-spatial-frequency error convergence at negligible stress. We found that controlling the subsidence and surface smoothing caused by material densification and melt under specific parameters range is an effective way to ensure both form error and roughness. Besides, an innovative "densi-melting" effect is further proposed to reveal the physical mechanism and guide the nano-precision figuring control, and the simulated results at different pulse durations fit well with the experiment results. Plus, to suppress the laser scanning ripples (mid-spatial-frequency (MSF) error) and reduce the control data volume, a clustered overlapping processing technology is proposed, where the laser processing in each sub-region is regarded as tool influence function (TIF). Through the overlapping control of TIF figuring depth, we achieved LBF experiments for the form error root mean square (RMS) reduced from 0.009λ to 0.003λ (λ=632.8 nm) without destroying microscale roughness (0.447 nm to 0.453 nm) and nanoscale roughness (0.290 nm to 0.269 nm). The establishment of the densi-melting effect and the clustered overlapping processing technology prove that LBF provides a new high-precision, low-cost manufacturing method for optics.

Fourier convolution-parallel neural network framework with library matching for multi-tool processing decision-making in optical fabrication

Intelligent manufacturing of ultra-precision optical surfaces is urgently desired but rather difficult to achieve due to the complex physical interactions involved. The development of data-oriented neural networks provides a new pathway, but existing networks cannot be adapted for optical fabrication with a high number of feature dimensions and a small specific dataset. In this Letter, for the first time to the best of our knowledge, a novel Fourier convolution-parallel neural network (FCPNN) framework with library matching was proposed to realize multi-tool processing decision-making, including basically all combination processing parameters (tool size and material, slurry type and removal rate). The number of feature dimensions required to achieve supervised learning with a hundred-level dataset is reduced by 3-5 orders of magnitude. Under the guidance of the proposed network model, a 260 mm × 260 mm off-axis parabolic (OAP) fused silica mirror successfully achieved error convergence after a multi-process involving grinding, figuring, and smoothing. The peak valley (PV) of the form error for the OAP fused silica mirror decreased from 15.153λ to 0.42λ and the root mean square (RMS) decreased from 2.944λ to 0.064λ in only 25.34 hours. This network framework has the potential to push the intelligence level of optical manufacturing to a new extreme.

Modeling and in-depth analysis of the mid-spatial-frequency error influenced by actual contact pressure distribution in sub-aperture polishing

In ultra-precision optical processing, the sub-aperture polishing is prone to produce a mid-spatial-frequency (MSF) error. However, the generation mechanism of the MSF error is still not fully clarified, which seriously affects the further improvement of optical component performance. In this paper, it is proved that the actual contact pressure distribution between the workpiece and tool is a crucial source which affects the MSF error characteristics. A rotational periodic convolution (RPC) model is proposed to reveal the quantitative relationship among the contact pressure distribution, speed ratio (spin velocity/feed speed) and MSF error distribution. In-depth analyses show that the MSF error is linearly related to the symmetry level of contact pressure distribution and inversely proportional to the speed ratio, where the symmetry level is effectively evaluated by the proposed method based on Zernike polynomials. In the experiments, according to the actual contact pressure distribution obtained from the pressure-sensitive paper, the error rate of modeling results under different processing conditions is around 15%, which proves the validity of the proposed model. The influence of contact pressure distribution on the MSF error is further clarified through the establishment of RPC model, which can further promote the development of sub-aperture polishing.

Pan-cancer analysis confirms the prognostic and immunological effects of prostate tumor overexpressed-1 in human cancers

BACKGROUND

Prostate tumor overexpressed-1 (PTOV1) is a conserved oncogenic adaptor protein associated with cancer progression and may be an independent prognostic marker for several malignancies. Consequently, using pan-cancer research to explore the significance of PTOV1 is valuable, and may reveal novel targets for cancer treatment.

METHODS

A comprehensive bioinformatics analysis of PTOV1 was performed. The qRT-PCR was utilized to confirm the aberrant PTOV1 expression in several cancer cell lines.

RESULTS

We observed that PTOV1 mRNA expression was high in 18 cancer tissues and was thereafter associated with poor survival prognosis in a range of malignancies. The immune subtypes of 14 malignancies and the molecular subtypes of six malignancies were related to PTOV1. A substantial association between PTOV1 and immune checkpoint (ICP) genes was also observed. Tumor mutational burden (TMB), microsatellite instability (MSI), and DNA methylation analyses indicated that PTOV1 acts as a cancer-promoting agent in a series of tumors. In addition, an enrichment study of PTOV1 and related genes revealed that RNA splicing may be responsible for the involvement of PTOV1 in cancers. Lastly, we also verified that PTOV1 expression was elevated in bladder cancer, breast cancer, CESC, LIHC cell lines via qRT-PCR.

CONCLUSION

Our bioinformatics research indicated that PTOV1 may be involved in tumor immunity. Furthermore, differentially expressed PTOV1 was found to be related to poor prognosis in cancers, and RNA splicing may be the specific mechanism for this effect. Therefore, PTOV1 mRNA and the corresponding protein may function as potential prognostic indicators and therapeutic targets in various cancers.

Statistical perception of the chaotic fabrication error and the self-adaptive processing decision in ultra-precision optical polishing

Subaperture polishing is a key technique for fabricating ultra-precision optics. However, the error source complexity in the polishing process creates large fabrication errors with chaotic characteristics that are difficult to predict using physical modelling. In this study, we first proved that the chaotic error is statistically predictable and developed a statistical chaotic-error perception (SCP) model. We confirmed that the coupling between the randomness characteristics of chaotic error (expectation and variance) and the polishing results follows an approximately linear relationship. Accordingly, the convolution fabrication formula based on the Preston equation was improved, and the form error evolution in each polishing cycle for various tools was quantitatively predicted. On this basis, a self-adaptive decision model that considers the chaotic-error influence was developed using the proposed mid- and low-spatial-frequency error criteria, which realises the automatic decision of the tool and processing parameters. An ultra-precision surface with equivalent accuracy can be stably realised via proper tool influence function (TIF) selection and modification, even for low-deterministic level tools. Experimental results indicated that the average prediction error in each convergence cycle was reduced to 6.14%. Without manual participation, the root mean square(RMS) of the surface figure of a ϕ100-mm flat mirror was converged to 1.788 nm with only robotic small-tool polishing, and that of a ϕ300-mm high-gradient ellipsoid mirror was converged to 0.008 λ. Additionally, the polishing efficiency was increased by 30% compared with that of manual polishing. The proposed SCP model offers insights that will help achieve advancement in the subaperture polishing process.

Liver PP2A-Cα Protects From Parenteral Nutrition-associated Hepatic Steatosis

BACKGROUND & AIMS

Parenteral nutrition (PN) is a lifesaving therapy for patients with intestinal failure. Hepatic steatosis is a potentially fatal complication of long-term PN, but the involved pathological mechanisms are incompletely unclarified. Herein, we identify the role of protein phosphatase 2A (PP2A) in the pathogenesis of parenteral nutrition-associated hepatic steatosis (PNAHS).

METHODS

Proteomic/phosphoproteomic analyses of liver samples from patients with PNAHS were applied to identify the mechanism of PNAHS. Total parenteral nutrition (TPN) mice model, in vivo, and in vitro experiments were used to assess the effect of PP2A-Cα on liver fatty acid metabolism.

RESULTS

Reduced expression of PP2A-Cα (catalytic subunit) enhanced activation of serine/threonine kinase Akt2 and decreased activation of adenosine monophosphate-activated protein kinase (AMPK) were associated with hepatic steatosis in patients with PNAHS. Mice given PN for 14 days developed hepatic steatosis, down-regulation of PP2A-Cα, activation of Akt2, and inhibition of AMPK. Hepatocyte-specific deletion of PP2A-Cα in mice given PN exacerbated Akt2 activation, AMPK inhibition, and hepatic steatosis through an effect on fatty acid degradation, whereas hepatocyte-specific PP2A-Cα overexpression significantly ameliorated hepatic steatosis accompanied with Akt2 suppression and AMPK activation. Additionally, pharmacological activation of Akt2 in mice overexpressing PP2A-Cα led to the aggravation of hepatic steatosis.

CONCLUSIONS

Our findings demonstrate that hepatic PP2A-Cα serves as a protective factor of PNAHS due to ameliorating hepatic steatosis and improving liver function. Our study provides a strong rationale that PP2A-Cα may be involved in the pathogenesis of PNAHS.

Iterative space-variant sphere-model deflectometry enabling designation-model-free measurement of the freeform surface

Freeform optics, offering high degrees of design freeform to control light propagation, have already been widely applied in various photoelectric equipment. The form quality of those optics is crucial to their opto-electronics functionalities, which requires to be measured accurately. The deflectometry is a promising technology to test the complex freeform surfaces. In general, there is a designed surface model for the monoscopic deflectometry to estimate the positions of whole measured points to solve the issue of height-slope ambiguity. However, the unknown or inaccurate surface model can induce errors into the measured normal, thereby decreasing the measurement precision. In this paper, without relying on the known surface model, the proposed method iteratively optimizes a sphere model to describe the measured surface by changing the spherical radius. In order to reduce the global error, the space-variant spheres are optimized, respectively, to estimate the whole-aperture surface coordinate. With the help of the iteration surface reconstruction process, the optimal number of the space-variant spheres is achieved to meantime obtain the final reconstructed surface. Compared to the measurements by using the plane model, the form accuracy can be improved by three times. Experiments demonstrate that the proposed method can successfully reconstruct the complex surfaces without the need of a known surface model, which can greatly improve the measuring flexibility and measurement accuracy.

Sparse bi-step raster path for suppressing the mid-spatial-frequency error by fluid jet polishing

The periodic ripple errors (mid-spatial-frequency (MSF) error) produced by computer-controlled sub-aperture polishing severely limit the improvement of high-performance optical systems. At the same time, the fluid jet polishing (FJP) method is non-destructive and non-contact, but it is still hard to widely use it due to the defect of small spot-size and low efficiency. In this paper, we found that FJP has a significant advantage in removing the residual periodic ripples in sub-aperture polishing. The mathematical model developed by complex spectrum optimization verifies the existence of the sparse "bi-step raster path" (BSRP), which can achieve efficient periodic ripple error removal by suppressing the first two-order peaks of the error spectrum. In the experiments, it was observed that the MSF error has been significantly reduced after BSRP processing while the surface form and surface roughness have not been deteriorated, which demonstrates the validity of the proposed method. The proposal of the BSRP provides a new approach for the application of FJP and the suppression of the MSF error.

High-efficiency smooth pseudo-random path planning for restraining the path ripple of robotic polishing

Computer-controlled subaperture polishing technology is limited by its propensity to introduce midspatial frequency (MSF) error (ripple error), which significantly inhibits the performance improvement of optical systems. The pseudo-random polishing path is an important method for suppressing MSF error. However, a pseudo-random path that ensures both path smoothness and planning efficiency is difficult to generate. This paper proposes a novel, to the best of our knowledge, pseudo-random path planning method employing a reconstructive points algorithm that efficiently achieves full coverage of the workpiece under massive sampling points at once. Moreover, the generation time for millions of path points is reduced to less than 3 minutes. Additionally, a path modification method is proposed that achieves smooth processing on a machine tool with few additional path points; the vibration magnitude under the proposed smooth path can be reduced to 0.749 g (gravity acceleration), which is the same as that of a raster path. A precise speed management method is also proposed to ensure precise surface error corrections. Overall, the experimental results show that the peak valley of the form error can be converted to 0.115λ using the proposed algorithm without introducing a periodic MSF error.

Survival Outcome with Routine Clinical Use of 82Rb PET/CT Myocardial Blood Flow (MBF) Quantification

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): NIHR Biomedical Research Centre, University College London Hospitals

Background

The prognostic value of 82Rb PET/CT derived myocardial blood flow (MBF) is increasingly recognised in both general and specific cardiovascular populations.

Purpose

This study investigates the prognostic potential of MBF in a large cohort of patients undergoing routine 82Rb PET/CT examination.

Methods

1148 consecutive patients (687 males, mean age 64 +/- 12 years) whom had been referred for 82Rb PET/CT examination in a single centre were included in this study.  All patients completed a stress 82Rb PET/CT with adenosine infusion, paired with a rest study.  Dynamic PET acquisitions were performed in both. Cardiovascular risk factors were documented as per clinical routine. Images were checked for quality and analysed using a proprietary software by an experienced operator to derive MBF parameters.  Overall survival was recorded following the study.

Results

Median follow-up period was 71 +/- 28 months.  Mean survival was 121 (95% CI: 118-124) months. On univariate analysis, global myocardial flow reserve <1.77 was associated with a higher all-cause mortality (p < 0.001). Other parameters including higher age (> =76 years), lower BMI (<21), qualitative abnormality on the myocardial perfusion scan (MPS), low hyperaemic ejection fraction on the gated studies (stress < 37 and rest < 34). Patients being on cardiac glycosides and diuretics were also significant predictor of poor prognosis (p < 0.001) on univariate analysis, presumably reflecting underlying arrhythmia and heart failure. A multivariate Cox regression analysis (step-wise Forward Wald), comprising of the above significant univariate markers, highlighted global myocardial flow reserve (HR: 2.6, 95%CI: 1.8-3.6, p < 0.001), age (HR: 2.8, 95%CI: 2.0-3.9, p < 0.001),, BMI (HR: 2.7, 95%CI: 1.7-4.1, p < 0.001),, ejection fraction (stress - HR: 3.3, 95%CI: 2.3-4.8, p < 0.001), MPS (HR: 1.5, 95%CI: 1.1-2.1, p = 0.024), and patients on diuretics (HR: 1.8, 95%CI: 1.2-2.5, p = 0.003) were independent predictors of overall survival (overall model: p < 0.001)

Discussion

We show that high volume routinely derived MBF in patients undergoing 82Rb PET/CT is a strong predictor of mortality and independent of other risk factors. This has important clinical implication for measuring not only interventional treatment but also measuring the effect of lifestyle and medical strategies.

Comprehensive mechanical & metabolic imaging of abdominal aortic aneurysm with 4D flow/ FDG PET on an integrated PETMRI: a feasibility study

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): NIHR Biomedical Research Centre, University College London Hospitals.

Background

A number of non-invasive imaging derived parameters have been implicated in the development and progression of abdominal aortic aneurysm, although the mechanism, and relationships of many of these are yet to be precisely determined.  Mechanical parameters can now be studied using 4D phase contrast magnetic resonance (PCMR), and inflammatory cellular activity can be detected with FDG PET.

Purpose

It may be postulated that inflammation of the aortic wall may be the intermediary at the tissue level linking mechanical wall shear stress (WSS) to aneurysm progression. It may be feasible to study 4D PCMR and FDG PET at the same patient visit on a PETMRI platform, with the potential to enhance temporal and spatial co-registration and improving the understanding of any relationship between these two parameters.  Our study aims to assess feasibility of studying these on an integrated PETMRI system.

Methods

7 patients with known aortic aneurysm were recruited in a vascular ultrasound screening follow up clinic.  During a single visit following 6 hours fasting, all patients underwent FDG injection and 60 minutes uptake period.  With quiet breathing, list mode PET acquisition and concurrent 4D PCMR was acquired using stacks of spiral acquisition, with ECG trace information for retrospective gating.  Images from the 4D PCMR and FDG PET were assessed qualitatively for image quality and visual matching.

Results

All 7 patients completed the study.  Overall image quality was adequate to good.  There is qualitatively a good concordance with impression of positive correlation between wall shear stress and inflammatory signal (see attached image).

Conclusion

We have demonstrated feasibility of combined assessment of mechanical and metabolic imaging parameters using an integrated PETMRI system.  Initial findings show there to be a broad concordance of wall shear stress and inflammatory signal in the abdominal aneurysm.

Modeling and prediction of tool influence function under complex edge in sub-aperture optical polishing

Edge mis-figures are regarded as one of the most difficult technical issues in optical fabrication. At present, only the near straight-line edge tool influence function (TIF) can be fitted by a polynomial function, but it is difficult to unify a 2-D analytical model suitable for complex edge workpieces and various tools, due to the lack of the scientific understanding of the edge removal behavior. In this paper, a comprehensive mathematical model is proposed to reveal the mechanism of the edge effect and accurately predict the complex edge TIF. The concept of a nonlinear edge kernel is first proposed and verified that the nonlinear pressure can be characterized by convoluting the kernel with the edge contour, which can be easily adapted to complex edge cases; besides, the edge kernel obtaining algorithm is established. The linear pressure part is verified to be constrained by the moment balance formula, which occurs in universal joint tool. Besides, the basic pressure distribution is presented to compensate the pressure distortion caused by the uneven form of the tool pad. The introducing of these three parts makes the complex edge pressure modeled efficiently and matched perfectly with the FEA results. In addition, a series of TIF experiments were carried out on various complex edge workpieces and different tools, which could be well predicted by the proposed model in 2-D view.

Novel double injection technique for sentinel lymph node biopsy in oral cancer

The development of new lymphatic tracers and the advancement of hybrid tracers, such as indocyanine green (ICG)-Nanocoll (GE Healthcare), represent an exciting step in the future of sentinel lymph node biopsy (SLNB). These tracers aim to improve our ability to detect sentinel lymph nodes by enhancing their localisation. The aim of this study was to assess the performance of a novel dual tracer, double injection technique of ICG-'cold'-Nanocoll and radiolabelled Nanocoll, in SLNB for early-stage oral cancer. A double injection technique was performed first using ^99mTc-Nancoll prior to sentinel node imaging followed by ICG-'cold'-Nanocoll injection in theatre. Analysis involved examination of the number, labelling, and location of the nodes harvested, sentinel node status, survival analysis, false negative rate, and complications associated with use of the technique. ICG 'cold' Nanocoll results showed concordance of fluorescence and radioactivity detection in 74 nodes in 24 patients. Most importantly, all nodes found positive for metastasis (6 nodes) were discovered to be both 'hot' and fluorescent; 74 nodes removed were both 'hot' and fluorescent, eight fluorescent only and six 'hot' only. Our results indicate that two sets of tracer injections given at two different time points will flow to the same sentinel nodes. This double labelling increased our confidence that the retrieved node was a sentinel node.

[Hepatic echinococcus granulosus: a clinicopathological analysis of thirteen cases]

Objective: To investigate the clinicopathologic characteristics of hepatic echinococcus granulosus (HEG). Methods: Thirteen cases of HEG were collected from Linzhi People's Hospital between January 2017 to October 2020, and their clinicopathologic features, ultrasound classification, immunophenotype and histochemical data were analyzed, retrospectively and the relevant literature was reviewed. Results: Thirteen patients (5 male patients, 8 female patients) were included in this cohort, and the mean age was 40 years. The most common clinical presentation was mild abdominal distention and pain (9/13). Based on WHO-IWGE ultrasound standardized classification, these cases were classified into 5 types, including type CL (1 case), type CE1 (2 cases), type CE2 (4 cases), type CE3 (3 cases) and type CE4 (3 cases). Gross examination revealed a solitary cyst localized in the liver, varying from 2.7 to 13.5 cm in diameter, and most of them(10/13)were more than 10 cm. Histopathologically, these cysts possessed a thin inner germinal layer and outer adventitial layer, and a central cavity filled with a clear"hydatid"fluid. The germinal layer was continuous and generated brood capsules and protoscoleces. The laminated membranes were clearly demonstrated by elastic fiber and Gomori's stains. Inside the"mother"cyst, there were a varying number of"daughter"vesicles of variable sizes. The inflammatory reaction around the cyst consisted of eosinophils, mononuclear cells immediately next to the cyst layer and sometimes formed granuloma and giant cells resembling the Langhan's type giant cells. The lymphoid cells were positive for CD20 and CD3. The CD68 immunohistochemistry clearly demonstrated epithelioid cells of granuloma in two cases. Moreover, immunohistochemistry revealed plasma cells were locally positive for CD38, IgG and IgG4, but not meeting the criteria for IgG4 related lesion. Conclusions: Hepatic echinococcus granulosus is a zoonotic parasitic disease prevalent in pastoral areas such as Tibet. It is important to understand its clinical features, ultrasound characteristics and histological morphology.

Unilateral axillary adenopathy following COVID-19 vaccination: a multimodality pictorial illustration and review of current guidelines

We present a multimodality pictorial review of axillary lymphadenopathy in patients recently vaccinated against COVID-19. As the mass vaccination programme continues to be rolled out worldwide in an effort to combat the pandemic, it is important that radiologists consider recent COVID-19 vaccination in the differential diagnosis of unilateral axillary lymphadenopathy and are aware of typical appearances across all imaging methods. We review current guidelines on the management of unilateral axillary lymphadenopathy in the context of recent COVID-19 vaccination.

Distributions of serum thyroid-stimulating hormone in 2020 thyroid disease-free adults from areas with different iodine levels: a cross-sectional survey in China

PURPOSE

The aim of the present study was to describe the distributions of serum thyroid- stimulating hormone (TSH) levels in thyroid disease-free adults from areas with different iodine levels in China. Meanwhile, we aimed to evaluate the influence of age and gender on the distribution of TSH, assess the relationship between concentrations of TSH and free thyroxine (FT₄), and analyze the factors that may affect TSH levels.

METHODS

2020 adults were included from April 2016 to June 2019. Urinary iodine concentration, serum iodine concentration, serum TSH, FT₄, free triiodothyronine, thyroid peroxidase antibodies and thyroglobulin antibodies were measured, and thyroid ultrasonography was performed.

RESULTS

The median of TSH in iodine-fortification areas (IFA), iodine-adequate areas (IAA), iodine-excessive areas (IEA) were 2.32, 2.11 and 2.34 mIU/L, respectively. Serum TSH concentrations were significantly higher in IFA and IEA than that in IAA (p = 0.005 and < 0.0001). The TSH values of most adults were distributed within the range of 1.01-3.00 mIU/L with the same trend in three groups. In our study, TSH levels did not change with age, and the TSH level of females was higher than that of males (p < 0.0001). There was a negative correlation between FT₄ and TSH in IAA (r = - 0.160, p < 0.0001) and IEA (r = - 0.177, p < 0.0001), but there was no correlation between FT₄ and TSH in IFA (r = - 0.046, p = 0.370). BMI, smoking status, education levels, and marital status were associated with TSH.

CONCLUSION

Our study provides a basis for establishing the reference intervals of TSH in different iodine level areas.

Can deep learning identify normal coronary flow reserve from rubidium myocardial PET perfusion?

Funding Acknowledgements

Type of funding sources: None.

Background

Impaired vasodilator function is an early manifestation of coronary artery disease (CAD) and may precede angiographic stenosis.  Rest and stress myocardial blood flow (MBF) are calculated from dynamic imaging during rest/stress Rubidium (Rb) myocardial PET perfusion.  Coronary flow reserve (CFR) equals stress divided by rest MBF.  CFR is an independent predictor of cardiac mortality in patients with known or suspected CAD.  We evaluated the prediction of CFR from analysis of stress/rest PET images by deep learning (DL) as compared with standard calculation of CFR using supervised learning applied methodology using within a commercial DL training platform.

Methods

1036 patients (625 male, 411 female, mean age: 64.3 years old) were studied. Patients underwent Stress/rest Rb PET perfusion, and CFR calculated using MBF software by an expert user. Abnormal CFR was defined as &lt;2.0. The left ventricle myocardium was segmented using standard software.

DL was trained using polar distribution of normalized PET uptake at stress and rest, processed stress and rest images were cropped, the stress images were then subtracted from the rest images. DL was trained using 935 subtracted images and tested using the remaining 101 images. DL was trained with supervision to classify images. The image shows examples of subtracted  abnormal cases (1a & 1b).

Results

Using our supervised training methodology, the commercial MBF software platform reported 465 cases as abnormal, with 48 of these were included in the DL test set. The DL platform produced abnormal output classifiers for all the whole test set. DL accurately detected over 70% of abnormal cases.

The commercial MBF software reported 571 cases as normal; with 50 of these contributing to the DL test set. DL was accurate in 48.0% of normal cases. Statistical results are shown in the table.

Conclusion

We have shown the proof of concept that DL algorithms trained with supervision can detect abnormal CFR. Our work shows that further work is needed to develop supervised learning methodology in order to improve accuracy for clinical use.

Statistical Results Statistic Value Sensitivity 63.16% Specificity 56.67% + Predictive Value 48.00% - Predictive Value 70.83% Accuracy 59.18% Abstract Figure.

Paediatric Molecular Radiotherapy: Challenges and Opportunities

The common contemporary indications for paediatric molecular radiotherapy (pMRT) are differentiated thyroid cancer and neuroblastoma. It may also have value in neuroendocrine cancers, and it is being investigated in clinical trials for other diseases. pMRT is the prototypical biomarker-driven, precision therapy, with a unique mode of delivery and mechanism of action. It is safe and well tolerated, compared with other treatments. However, its full potential has not yet been achieved, and its wider use faces a number of challenges and obstacles. Paradoxically, the success of radioactive iodine as a curative treatment for metastatic thyroid cancer has led to a 'one size fits all' approach and limited academic enquiry into optimisation of the conventional treatment regimen, until very recently. Second, the specialised requirements for the delivery of pMRT are available in only a very limited number of centres. This limited capacity and geographical coverage results in reduced accessibility. With few enthusiastic advocates for this treatment modality, investment in research to improve treatments and broaden indications from both industry and national and charitable research funders has historically been suboptimal. Nonetheless, there is now an increasing interest in the opportunities offered by pMRT. Increased research funding has been allocated, and technical developments that will permit innovative approaches in pMRT are available for exploration. A new portfolio of clinical trials is being assembled. These studies should help to move at least some paediatric treatments from simply palliative use into potentially curative protocols. Therapeutic strategies require modification and optimisation to achieve this. The delivery should be personalised and tailored appropriately, with a comprehensive evaluation of tumour and organ-at-risk dosimetry, in alignment with the external beam model of radiotherapy. This article gives an overview of the current status of pMRT, indicating the barriers to progress and identifying ways in which these may be overcome.

Iron overload is related to muscle wasting in patients with cachexia of gastric cancer: using quantitative proteome analysis

The incidence of gastric cancer cachexia is high and the clinical management is poor, so the study aimed to clarify the mechanism of muscle wasting to better screen patients with gastric cancer cachexia. Gastric cancer patients undergoing radical gastrectomy were divided into cachexia with sarcopenia (CS, n = 13) and normal (N, n = 10) two groups. The possible mechanism of skeletal muscle reduction was explored through Tandem Mass Tag (TMT) technique, Perls staining, Western blot analysis and measurement of oxidative stress indicators. The preoperative weight, weight loss, body mass index, calorie intake and skeletal muscle index values of the CS group were significantly lower than those of the N group (P < 0.05). We identified 114 differentially expressed proteins (DEP) in the muscles of two groups using TMT analysis. Bioinformatics analysis of DEP revealed that ferritin, iron and oxidative stress may be related to skeletal muscle consumption. Following Perls staining and measurement iron concentration in skeletal muscles, we found that the iron in the muscles of the CS group was significantly increased, and at the same time, western blot analysis showed that the expression of ferritin in the CS group was significantly increased and regulated by hepcidin-ferroportin axis. Finally, the CS group showed increased oxidative stress and weakened antioxidant stress systems in the muscles compared with the N group when oxidative stress indicators were analyzed. In conclusion, iron overload may be related to muscle loss in patients with gastric cancer cachexia. Gastric cancer patients with elevated ferritin are more likely to have muscle wasting.

Nonthyroidal Illness Syndrome in Patients With Short-Bowel Syndrome

BACKGROUND

Nonthyroidal illness syndrome (NTIS) is prevalent in critical illness and is associated with poor outcomes. However, only few studies have focused on the relationship between NTIS and short-bowel syndrome (SBS). The aim of this study was to investigate the prevalence, etiology, and prognosis of NTIS and its correlation with clinical variables in adult patients with SBS.

METHODS

Sixty-one eligible adults diagnosed with SBS, from December 2016 to December 2018, were retrospectively identified from a prospectively maintained database. Demographic and clinical characteristics (including thyroid hormones and nutrition variables) were evaluated for each participant.

RESULTS

The prevalence of NTIS in adults with SBS was 52.5%. Patients with NTIS tended to have a longer duration of hospital stay and poor survival, but the results were not significant. A decreased, standard thyroid-stimulating hormone index and sum activity of deiodinases and an increased secretory capacity by the thyroid were observed in the NTIS group. Receiver operating characteristic curve analysis showed that insulin-like growth factor-1 (IGF-1) had better performance for distinguishing NTIS from patients with euthyroidism, with an area under the curve of 0.862 (cutoff, 101.0; sensitivity, 0.813; and specificity, 0.800).

CONCLUSIONS

NTIS is a common complication in adult patients with SBS. Patients with NTIS tend to have a worse nutrition status and poor prognosis. A potential pituitary thyrotroph dysfunction and hypodeiodination condition may play a role in the pathophysiology of NTIS in SBS. Furthermore, IGF-1 is a meaningful predictor for distinguishing NTIS from euthyroid.

Modeling and analysis of the mid-spatial- frequency error characteristics and generation mechanism in sub-aperture optical polishing

In the field of ultra-precision manufacturing, the mid-spatial-frequency (MSF) error can severely affect the performance of the optical elements, but it is rather difficult to quantitatively predict the MSF error distribution. In this paper, the piecewise-path convolution (PPC) analysis is established to investigate the characteristic and the mechanism of the MSF error. The path type, tool influence function (TIF), feed rate, movement type, etc. are all considered mathematically in the analysis. This method can quantitatively predict the MSF error distribution. The coupling relationship among the path type, TIF and the MSF error are proved through the filtering theory. Besides, the analysis reveals the mathematical relationship between the tool movement type (orbital motion, radial runout) and the MSF error; the results show that the tool motion can also introduce non-negligible MSF error. Based on the research above, two selection formulae of path type, TIF and polishing parameters are provided for low MSF error polishing, which gives the theoretical guidance for the parameter selection in deterministic polishing. Practical experiments demonstrate the validity of the analysis results and conclusions.

Prolonged Parenteral Nutrition Is One of the Most Significant Risk Factors for Nosocomial Infections in Adult Patients With Intestinal Failure

BACKGROUND

Intestinal failure (IF) and its management are associated with an increased likelihood of infectious complications. This study aimed to evaluate the prevalence and potential risk factors for nosocomial infections (NIs) in hospitalized adult patients with IF.

METHODS

In total, 259 eligible patients with IF admitted to a single clinical nutrition center in a tertiary referral hospital from January 1, 2012, to January 1, 2019, were retrospectively identified. NIs were defined according to the 2008 Centers for Disease Control and Prevention criteria. Univariate and multivariate analyses were performed to identify independent risk factors for NIs.

RESULTS

The mean age of the study population was 47.0 ± 17.7 years, and 158 (61.0%) were men. The mean body mass index was 16.2 ± 2.9 kg/m² , and 219 (84.6%) were diagnosed with malnutrition. The prevalence of NIs was 25.5% (113 NIs in 66 patients). The most common NIs were pneumonia (14.3%), bacteremia of unknown origin (13.5%), catheter-related bloodstream infection (5.0%), lower respiratory tract infection (5.0%), surgical site infection (3.9%), and urinary tract infection (1.9%). Multivariate analysis revealed that decreased serum albumin level (odds ratio [OR], 0.884; 95% CI, 0.883-0.978, P < .05), presence of gallbladder stones or cholestasis (OR, 3.144; 95% CI, 1.044-9.464; P < .05), and prolonged parenteral nutrition (PN) use (OR, 1.072; 95% CI, 1.039-1.105; P < .001) were independent predictors for NIs.

CONCLUSIONS

NIs remain prevalent in hospitalized adult patients with IF. Prolonged PN use was one of the most significant predictors for NIs.

Superior Mesenteric Artery Syndrome Improved by Enteral Nutritional Therapy: A Retrospective Case-Series Study in a Single Institution

INTRODUCTION

Superior mesenteric artery syndrome (SMAS) is a relatively rare cause of chronic duodenal obstruction, owing to the compression of the third portion of the duodenum.

OBJECTIVES

This retrospective study aims to discuss the efficacy of enteral nutrition (EN) therapy in nutritional status and symptom improvement at a short-term follow-up for SMAS patients.

METHODS

We retrospectively analyzed clinical data of patients diagnosed as SMAS and treated with EN from September 2012 to January 2019.

RESULTS

Twenty-six patients were included (16 women; mean age 24.96 ± 11.77 years), none was excluded, and one was lost to follow-up. The patients' mean body weight was 40.94 ± 10.16 kg, mean weight loss 11.73 ± 7.58 kg, and mean body mass index (BMI) 14.82 ± 2.52 kg/m2. The mean duration of EN therapy was 10.10 ± 4.66 months. Serum level of nutritional indicators, BMI and body weight increased after EN therapy. During a median follow-up of 24 months (9-44) after EN therapy, the mean symptom score decreased from 24.28 ± 9.57 to 8.06 ± 8.29 (p < 0.0001), and 65% of patients' symptoms resolved and 15% of patients' symptoms improved. In total, 16 complications occurred, including tube blockage, peristomal wound infections, peristomal leakage, granulomas, and nasopharyngeal pain.

CONCLUSION

EN therapy may be an effective option for SMAS patients. While it might not remove all symptoms, it can improve the nutritional status to support subsequent treatments.

Benign temporomandibular joint tumours with extension to infratemporal fossa and skull base: condyle preserving approach

This article introduces a modified surgical approach combining condylotomy with posterior disc attachment release for the resection of large non-malignant masses located in the infratemporal fossa and involving the skull base. This retrospective study included 14 patients treated at Shanghai Ninth People's Hospital, Shanghai Jiao Tong University between January 2010 and December 2016. Clinical evaluations (visual analogue scale (VAS) for pain, maximum inter-incisal opening (MIO), and complications) and radiological findings (magnetic resonance imaging (MRI) and computed tomography (CT)) were collected pre- and postoperatively. All patients had satisfactory surgical exposure and complete resection of the neoplasms. During an average follow-up of 54.8 months, no clinical or radiographic signs of recurrence were reported. MIO increased from 28mm preoperatively to 35.4mm postoperatively (P<0.001). The pain VAS score changed from 5.4 preoperatively to 0.7 postoperatively (P<0.001). Neural function was normal for all patients. Postoperative MRI and CT scans showed a satisfactory disc position and condyle morphology, with no resorption. Three-dimensional reconstruction of the postoperative CT scan also demonstrated healing of the skull base defects. The modified surgical approach combining condylotomy with posterior disc attachment release is suitable for the removal of large non-malignant masses involving the infratemporal fossa and skull base.

Risk Factors for Nephrolithiasis in Adults with Short Bowel Syndrome

INTRODUCTION

Patients with short bowel syndrome (SBS) commonly develop nephrolithiasis. However, the risk factors for nephrolithiasis in patients with SBS remain unclarified. The present study aimed to identify the risk factors for nephrolithiasis in adults with SBS.

METHODS

All eligible adults diagnosed with SBS and admitted to a tertiary referral center from December 2008 to 2018 were retrospectively identified from a prospectively maintained database. Patients' demographic and clinical characteristics were analyzed using univariate and multivariate analyses to identify the risk factors for nephrolithiasis.

RESULTS

Of 231 adults with SBS, 42 (18.2%) developed nephrolithiasis. The mean age was 46.4 ± 17.8 years, the mean body mass index was 18.2 ± 3.8 kg/m2, and median duration of SBS was 11 months (range 2-324 months). Multivariate binary logistic regression analysis revealed that the independent risk factors for nephrolithiasis in adults with SBS were jejuno-ileal anastomosis and colon-in-continuity (OR 4.335; 95% CI 1.175-16.002; p = 0.028), prolonged duration of SBS (OR 1.008; 95% CI 1.002-1.014; p = 0.010), and increased serum creatinine concentration (OR 1.005; 95% CI 1.001-1.009; p = 0.012).

CONCLUSIONS

Nephrolithiasis is common in adults with SBS. As nephrolithiasis can have adverse clinical consequences, patients with SBS should be closely monitored, and prophylactic interventions should be considered.

Correction to 'Resveratrol-loaded PLGA nanoparticles: enhanced stability, solubility and bioactivity of resveratrol for non-alcoholic fatty liver disease therapy'

[This corrects the article DOI: 10.1098/rsos.181457.].

Region-adaptive path planning for precision optical polishing with industrial robots

In the field of ultra-precision manufacturing, industrial robotic polishing has the potential to become a more economical and intelligent method than the conventional polishing machines. But the challenge of the robotic polishing lies in the low control accuracy, which seriously affects the polishing quality. In this paper a new region-adaptive path planning method is proposed, where the path is generated adaptively according to the specific form error. Each time only the regions with form error large enough are processed, thereby improving the polishing stability and efficiency. Smooth paths are generated based on the hexagonal meshing of the processing regions to avoid sharp turning, and then the dwell time is calculated by space-variant deconvolution. The PVr metric of the final form error resulting from the robotic polisher converges down to λ/15. In addition this method can reduce the polishing time by 80%, henceforth the stability and efficiency of robotic polishing can be greatly improved.

Depolymerization of sodium polyphosphates on an iron oxide surface at high temperature

Density functional theory (DFT) and first principles molecular dynamics (FPMD) studies of pyrophosphate cluster Na₄P₂O₇ and triphosphate cluster Na₅P₃O₁₀ absorbed and decomposed on an Fe₂O₃(0001) surface have been conducted. Comparative analyses of the structure properties and adsorption processes during the simulation at elevated temperature have been carried out. The results depict the key interactions including the covalent P-O bonds, pure ionic Na-O or Fe-O interactions. The iron oxide surface plays an important role in the bridging bond decomposition scheme which can both promote and suppress phosphate depolymerization. It is found that the chain length of polyphosphates does not have considerable effects on the decomposition of phosphate clusters. This study provides detailed insights into the interaction of a phosphate cluster on an iron oxide surface at high temperature, and in particular the depolymerization/polymerization of an inorganic phosphate glass lubricant, which has an important behavior under hot metal forming conditions.

High Fructose and High Fat Exert Different Effects on Changes in Trabecular Bone Micro-structure

OBJECTIVES

To compare the effects of high-fat diet (HFD) and high-fructose diet (HFrD) on bone metabolism at different time points, dynamically observe the bone histology and femur trabecular micro-architecture, and analyze the underlying mechanisms.

METHODS

Sixty -Five male 6- to 7-week-old C57BL/6J mice were given HFD, HFrD, or standard diets (SD) for 8, 16, and 24 weeks. Micro-computed tomography (μCT) and bone histology were used to measure bone mass and trabecular micro-structure. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression of genes related to bone and lipid metabolisms.

RESULTS

Compared to SD mice, femoral trabecular bone mass was significantly increased in both HFrD mice and HFD mice at 8 weeks, it continued to be higher in HFrD mice at 16 and 24 weeks with the highest level at 16 weeks, but it was significantly decreased in HFD mice at 16 and 24 weeks. HFD mice showed more epididymal fat accumulation than HFrD mice. mRNA expression of Runx2 was up-regulated at 8 and 16 weeks, but down-regulated at 24 weeks similarly in both HFrD mice and HFD mice. mRNA expression of MMP9 and CTSK was up-regulated at 8 and 16 weeks in HFD mice, but down-regulated at 24 weeks in both HFrD mice and HFD mice.

CONCLUSIONS

Our data indicated that the HFrD and HFD had different modulating effects on bone mass. After short-term feeding, both HFrD and HFD showed positive effects on bone mass; however, after long-term feeding, bone mass was decreased in HFD mice. In contrast, the bone mass was first increased and then decreased in the HFrD mice. On the basis of these findings, we speculated that chronic consumption of fat and fructose would exert detrimental effects on bone mass which might a combination action of body mass, fat mass, and bone formation/bone resorption along with proinflammatory factor and bone marrow environment.

Evaluation of a visual tool co-developed for training hospital staff on the prevention and control of the spread of healthcare associated infections

BACKGROUND

Staff training in infection prevention and control (IPC) across hospital settings has a crucial role in reducing the incidence of healthcare associated infections (HAIs). However the application of dynamic visualisation approaches in this context is under-developed, with very few in-depth evaluation studies of related processes and impacts.

METHODS

A prototype training tablet app for hospital staff, using interactive visuals was developed and evaluated. To demonstrate different pathogen behaviour, dynamic visualisations of norovirus, Clostridium difficile, and MRSA were developed in relation to location, survival and transmission within a virtual hospital ward model using evidence-based microbiological and staff behavioural data. A three-stage evaluation process was designed, involving a mixed sample of UK National Health Service staff (doctors, nurses and domestic staff, n = 150).

RESULTS

Participants reported improved awareness and understanding of the pathogens responsible for HAI, the types of information relevant for different staff cohorts, those aspects of the visualisations which worked well and those which were prone to cause misunderstandings, and suggestions for further development and improvement. The tool appeared to offer staff a new perspective on pathogens, being able to 'see' them contextualised in the virtual ward, making them seem more real.

CONCLUSION

Results showed the benefits of a detailed co-development process and a more contextualised understanding of the potential for visual apps to be used in IPC training.

Urinary F2 -Isoprostanes in Cats with International Renal Interest Society Stage 1-4 Chronic Kidney Disease

BACKGROUND

F₂ -isoprostanes, a biomarker of oxidant injury, increase with advancing chronic kidney disease (CKD) in humans. In cats, the relationship between CKD and oxidative stress is poorly understood.

OBJECTIVES

To determine whether cats with advancing CKD have increasing urinary F₂ -isoprostanes.

ANIMALS

Control cats without evidence of CKD (≥6 years old; n = 11), and cats with IRIS stage 1 (n = 8), 2 (n = 38), 3 (n = 21), and 4 (n = 10) CKD.

METHODS

This was a prospective observational study. Urinary F₂ -isoprostanes (specifically free 15-F_2t -isoprostanes) normalized to urine creatinine (IsoPs) were compared among groups and tested for correlations with blood pressure, proteinuria, serum creatinine concentration, and urine specific gravity. The IsoPs also were compared between cats with and without hypertension or proteinuria, and in cats fed predominantly standard versus renal diets.

RESULTS

Urinary IsoPs were increased, but not significantly, in cats with stage 1 CKD (median 263 pg/mg creatinine; range, 211-380) compared to controls (182 pg/mg; range, 80-348) and decreased significantly from stage 1 through advancing CKD (stage 2, 144 pg/mg; range, 49-608; stage 3, 102 pg/mg; range, 25-158; stage 4, 67 pg/mg; range, 26-117; P < .01). Urinary IsoPs were inversely correlated with serum creatinine (r = -0.66, P < .0001).

CONCLUSION AND CLINICAL IMPORTANCE

Urinary IsoPs are significantly higher in early CKD (stage 1) compared to cats with more advanced CKD. Additional studies are warranted to characterize oxidative stress in cats with stage 1 CKD and determine whether early antioxidant treatments have a protective effect on CKD progression.

Modeling of edge effect in subaperture tool influence functions of computer controlled optical surfacing

Computer controlled optical surfacing requires an accurate tool influence function (TIF) for reliable path planning and deterministic fabrication. Near the edge of the workpieces, the TIF has a nonlinear removal behavior, which will cause a severe edge-roll phenomenon. In the present paper, a new edge pressure model is developed based on the finite element analysis results. The model is represented as the product of a basic pressure function and a correcting function. The basic pressure distribution is calculated according to the surface shape of the polishing pad, and the correcting function is used to compensate the errors caused by the edge effect. Practical experimental results demonstrate that the new model can accurately predict the edge TIFs with different overhang ratios. The relative error of the new edge model can be reduced to 15%.

Local Anaesthetic Toxicity after Bilateral Thoracic Paravertebral Block in Patients Undergoing Coronary Artery Bypass Surgery

We conducted a small pilot observational study of the effects of bilateral thoracic paravertebral block (BTPB) as an adjunct to perioperative analgesia in coronary artery bypass surgery patients. The initial ropivacaine dose prior to induction of general anaesthesia was 3 mg/kg, which was followed at the end of the surgery by infusion of ropivacaine 0.25% 0.1 ml/kg/hour on each side (e.g. total 35 mg/hour for a 70 kg person). The BTPB did not eliminate the need for supplemental opioids after CABG in the eight patients studied. Moreover, in spite of boluses that were within the manufacturer's recommendation for epidural and major nerve blocks, and an infusion rate that was only slightly higher than what appeared to be safe for epidural infusion, potentially toxic total plasma ropivacaine concentrations were common. We also could not exclude the possibility that the high ropivacaine concentrations were contributing to postoperative mental state changes in the postoperative period. Also, one patient developed local anaesthetic toxicity after the bilateral paravertebral dose. As a result, the study was terminated early after four days. The question of whether paravertebral block confers benefits in cardiac surgery remains unanswered. However, we believe that the bolus dosage and the injection rate we used for BTPB were both too high, and caution other clinicians against the use of these doses. Future studies on the use of BTPB in cardiac surgery patients should include reduced ropivacaine doses injected over longer periods.

Differential Proteomics Analysis of Colonic Tissues in Patients of Slow Transit Constipation

Objective. To investigate and screen the different expression of proteins in STC and normal group with a comparative proteomic approach. Methods. Two-dimensional electrophoresis was applied to separate the proteins in specimens from both 5 STC patients and 5 normal controls. The proteins with statistically significant differential expression between two groups were identified by computer aided image analysis and matrix assisted laser desorption ionization tandem time of flight mass spectrometry (MALDI-TOF-MS). Results. A total of 239 protein spots were identified in the average gel of the normal control and 215 in patients with STC. A total of 197 protein spots were matched and the mean matching rate was 82%. There were 14 protein spots which were expressed with statistically significant differences from others. Of those 14 protein spots, the expression of 12 spots increased markedly, while that of 2 spots decreased significantly. Conclusion. The proteomics expression in colonic specimens of STC patients is statistically significantly different from that of normal control, which may be associated with the pathogenesis of STC.