Theoretical Analysis of Thermophysical Properties of 3D Carbon/Epoxy Braided Composites with Varying Temperature.

A three-dimensional helix geometry unit cell is established to simulate the complex spatial configuration of 3D braided composites. Initially, different types of yarn factors, such as yarn path, cross-sectional shape, properties, and braid direction, are explained. Then, the multiphase finite element method is used to develop a new theoretical calculation procedure based on the unit cell for predicting the impacts of environmental temperature on the thermophysical properties of 3D four-direction carbon/epoxy braided composites. The changing rule and distribution characteristics of the thermophysical properties for 3D four-direction carbon/epoxy braided composites are obtained at temperatures ranging from room temperature to 200 °C. The influences of environmental temperature on the coefficients of thermal expansion (CTE) and the coefficients of thermal conduction (CTC) are evaluated, by which some important conclusions are drawn. A comparison is conducted between theoretical and experimental results, revealing that variations in temperature exert a notable influence on the thermophysical characteristics of 3D four-directional carbon/epoxy braided composites. The theoretical calculation procedure is an effective tool for the mechanical property analysis of composite materials with complex geometries.

Cell atlas of CCl 4-induced progressive liver fibrosis reveals stage-specific responses.

Chronic liver injury leads to progressive liver fibrosis and ultimately cirrhosis, a major cause of morbidity and mortality worldwide. However, there are currently no effective anti-fibrotic therapies available, especially for late-stage patients, which is partly attributed to the major knowledge gap regarding liver cell heterogeneity and cell-specific responses in different fibrosis stages. To reveal the multicellular networks regulating mammalian liver fibrosis from mild to severe phenotypes, we generated a single-nucleus transcriptomic atlas encompassing 49 919 nuclei corresponding to all main liver cell types at different stages of murine carbon tetrachloride (CCl 4)-induced progressive liver fibrosis. Integrative analysis distinguished the sequential responses to injury of hepatocytes, hepatic stellate cells and endothelial cells. Moreover, we reconstructed cell-cell interactions and gene regulatory networks implicated in these processes. These integrative analyses uncovered previously overlooked aspects of hepatocyte proliferation exhaustion and disrupted pericentral metabolic functions, dysfunction for clearance by apoptosis of activated hepatic stellate cells, accumulation of pro-fibrotic signals, and the switch from an anti-angiogenic to a pro-angiogenic program during CCl 4-induced progressive liver fibrosis. Our dataset thus constitutes a useful resource for understanding the molecular basis of progressive liver fibrosis using a relevant animal model.

Diagnostic value of an enhanced MRI combined with serum CEA, CA19-9, CA125 and CA72-4 in the liver metastasis of colorectal cancer.

OBJECTIVE: This paper aims to explore the diagnostic value of enhanced magnetic resonance imaging (MRI) combined with a carcinoembryonic antigen (CEA) and carbohydrate antigen in terms of the liver metastasis of colorectal cancer. METHODS: A total of 167 colorectal cancer patients with liver metastasis and 167 colorectal cancer patients without liver metastasis were selected as the subjects. An automatic electrochemiluminescence analyser was then used to detect the tumour markers CEA, CA19-9, CA125 and CA72-4. The consistency between the MRI examination and clinical pathological examination was also analysed, and the sensitivity, specificity and positive and negative predictive values of various combined detection methods were compared. RESULTS: The abnormal rates of CEA, CA19-9, CA125 and CA72-4 in the two groups were statistically significant (P < 0.05), while the results of the enhanced MRI and clinicopathological examination for liver metastasis in patients with colon cancer were largely consistent (Kappa coefficient = 0.788, P < 0.000). However, the two methods were inconsistent. The false positive rate of the enhanced MRI examination was 15.3%, while the false negative rate was 6.0%. The specificity (94.61%), positive predictive value (92.68%) and positive likelihood ratio (12.67%) were the highest for the MRI combined with serial CEA, while the sensitivity (98.80%) and negative predictive value (97.22%) were the highest with the MRI combined with parallel CEA, and this combination returned the lowest negative likelihood ratio (0.03). CONCLUSION: The combination of MRI and CEA excludes non-metastatic patients and identifies colorectal liver metastasis cancer patients. Overall, it has a higher diagnostic value.

DTI metrics can be used as biomarkers to determine the therapeutic effect of stem cells in acute peripheral nerve injury.

PURPOSE: To determine the role of diffusion tensor imaging (DTI) metrics as biomarkers for the therapeutic effects of mesenchymal stem cells (MSCs) in acute peripheral nerve injury. MATERIALS AND METHODS: Forty-four adult rats received subepineurial microinjection of MSCs (n = 22) or phosphate buffered saline (PBS, n = 22) 1 week after the sciatic nerve trunk crush injury. Sequential fat-suppressed T2-weighted imaging, T2 measurement, DTI and sciatic nerve functional assessment were performed at a 3.0 Tesla MR unit over an 8-week follow-up, with histological assessments performed at regular intervals. The sciatic nerve function index, T2 value, and DTI metrics, including fractional anisotropy (FA), axial diffusivity, radial diffusivity (RD), and mean diffusivity values of the distal stumps of crushed nerves were measured and compared between the two groups. RESULTS: Nerves treated with MSCs showed better functional recovery and exhibited more pronounced nerve regeneration compared with nerves treated with PBS. T2 values in nerves treated with MSCs or PBS showed a similar change pattern (P = 0.174), while FA and RD values in nerves treated with MSCs showed more rapid return (one week earlier) to baseline level than nerves treated with PBS (P = 0.045; 0.035). Nerves treated with MSCs had higher FA and lower RD values than nerves treated with PBS during the period from 2 to 3 weeks after surgery (P ≤ 0.0001, 0.004; P = 0.004, 0.006). CONCLUSION: FA and RD values derived from DTI might be used as sensitive biomarkers for detecting the therapeutic effect of stem cells in acute peripheral nerve crush injuries. LEVEL OF EVIDENCE: 2 J. Magn. Reson. Imaging 2017;45:855-862.

Diffusion tensor imaging of symptomatic nerve roots in patients with cervical disc herniation.

RATIONALE AND OBJECTIVES: Cervical disc degeneration can result in nerve root compression and severe symptoms that significantly impair the patient's quality of life. The purpose of this study is to investigate multiple diffusion metrics changes in the diffusion tensor imaging (DTI) of cervical nerve roots and their relationship with the clinical severity of patients with cervical disc herniation. MATERIALS AND METHODS: High directional DTI of the cervical nerve roots was performed in 18 symptomatic patients and 10 healthy volunteers with a 3.0-T magnetic resonance system after a routine cervical disc scanning. The fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were calculated from the DTI data and compared between the affected and unaffected sides in the same patient and between healthy volunteers and symptomatic patients. The correlation between the side-to-side diffusion metric differences and the clinical International Standards for Neurological Classification of Spinal Cord Injury scores was analyzed. RESULTS: C5-C8 nerve roots were clearly delineated with DTI. The FA, MD, AD, and RD of compressed nerve roots were 0.31 ± 0.091, 2.06 ± 0.536, 2.69 ± 0.657, and 1.75 ± 0.510 mm(2)/s, respectively. Compared to the unaffected side or healthy volunteers, the nerve roots of the affected side showed decreased FA (P < .022) and increased MD (P < .035), AD (P < .047), and RD (P < .012). The clinical International Standards for Neurological Classification of Spinal Cord Injury scores of the patients were negatively correlated with MD (r = -0.57, P = .002), AD (r = -0.451, P = .021), and RD (r = -0.564, P = .003) but not with FA (r = 0.004, P = .984). CONCLUSIONS: DTI can potentially be used to assess microstructural abnormalities in the cervical nerve roots in patients with disc herniation.

Variations of urinary bladder and the urogenital fatty fascial compartment with different filling of the bladder are notable factors relevant to hernia repair-related bladder injury.

The present study investigated bladder and urogenital fatty fascial compartment (UFFC) variations during bladder filling in an attempt to identify other possible causes of hernia repair-related bladder injury besides mesh migration. The study included 30 patients scheduled for abdominal computed tomography (CT) scan for nonhernia diseases. Sixty-four-slice CT scan was performed immediately after urination and no more than 30 minutes later. Three-dimensional images were constructed by two independent experienced readers. The empty bladder was triangular in shape, narrow in the front and broad in the rear. Its vertex deviated from midline of the abdominal wall in 11 cases (36.7%).With normal filling, it appeared as an irregular oval shape. Only two cases (6.7%) of empty bladder extended inside Hesselbach's triangle. However, this area was occupied to some extent in all cases during bladder filling (P = 0.003). The UFFC formed a molar-like structure in cross-section. In three dimensions, it appeared as an inverted V-shaped structure from the front. In the lateral view it appeared as a spoon that contained the bladder. UFFC volume increased from 61.85 ± 6.23 to 139.23 ± 5.29 cm(3) with bladder filling (P < 0.0001). The UFFC can be clearly identified by CT scanning or three-dimensional reconstruction. The considerable spatial variation of the UFFC and movement and deformation of the mesh within this area may be related to bladder injury.