Microbial induced calcium carbonate precipitation (MICP) refers to the natural biological process of calcium carbonate precipitation induced by microbial metabolism in its surrounding environment. Based on the principles of MICP, microbial cement has been developed and has received widespread attention in the field of biology, civil engineering, and environment owing to the merits of environmental friendliness and economic competence. Urease and carbonic anhydrase are the key enzymes closely related to microbial cement. This review summarizes the genes, protein structures, regulatory mechanisms, engineering strains and mutual synergistic relationship of these two enzymes. The application of bioinformatics and synthetic biology is expected to develop biocement with a wide range of environmental adaptability and high performance, and will bring the MICP research to a new height.
Calcium Carbonate/metabolism* ; Chemical Precipitation ; Urease/metabolism*

Objective:To investigate the diagnostic performance of MRI Liver Imaging Reporting and Data System version 2018 in high-risk hepatocellular carcinoma (HCC) patients with intrahepatic parenchymal substantial lesions ≤3.0 cm.Methods:A retrospective analysis was conducted in hospitals between September 2014 to April 2020. 131 pathologically confirmed non-HCC cases with lesions ≤3.0 cm in diameter were randomly matched with 131 cases with lesions ≤3.0 cm in diameter and divided into benign (56 cases), other hepatic malignant tumor (OM, 75 cases), and HCC group (131 cases) in a 1:1 ratio. MRI features of the lesions were analyzed and classified according to LI-RADS v2018 criteria (tie-break rule was applied to lesions with both HCC and LR-M features). Taking the pathological results as the gold standard, the sensitivity and specificity of the LI-RADS v2018 classification criteria and the more stringent LR-5 criteria (with three main signs of HCC at the same time) were calculated for HCC, OM or benign lesions diagnosis. Mann -Whitney U test was used to compare the classification results. Results:The number of cases classified as LR-M, LR-1, LR-2, LR-3, LR-4, and LR-5 in HCC group after applying the tie-break rule were 14, 0, 0, 12, 28, and 77, respectively. There were 40, 0, 0, 4, 17, 14 and 8, 5, 1, 26, 13, 3 cases in benign and OM group, respectively. There were 41 (41/77), 4 (4/14) and 1 (1/3) lesion case in the HCC, OM and benign group, respectively, that met the more stringent LR-5 criteria. The sensitivity of LR-4 combined with LR-5 (LR-4/5) criteria, LR-5 criteria and more stringent LR-5 criteria for HCC diagnosis were 80.2% (105/131), 58.8% (77/131) and 31.3% (41/131), respectively, and the specificity were 64.1% (84/131), 87.0% (114/131) and 96.2% (126/131), respectively. The sensitivity and specificity of LR-M were 53.3% (40/75) and 88.2% (165/187), respectively. The sensitivity and specificity using LR-1 combined with LR-2 (LR-1/2) criteria for the diagnosis of benign liver lesions were 10.7% (6/56) and 100% (206/206), respectively.Conclusions:LR-1/2, LR-5, and LR-M criteria have high diagnostic specificity for intrahepatic lesions with a diameter of ≤3.0 cm. Lesions classified as LR-3 are more likely to be benign. The specificity of LR-4/5 criteria is low, while the more stringent LR-5 criteria has a high specificity for HCC diagnosis.

Objective:To evaluate the value of the crescent sign for predicting the invasiveness of lung adenocarcinoma presenting as pure ground-glass nodule (pGGN).Methods:The clinical, pathological and imaging data of 316 patients (320 pGGNs) confirmed lung adenocarcinoma by surgery and pathology from July 2013 to June 2018 in the First Affiliated Hospital of Wenzhou Medical University were retrospectively analyzed. All pGGNs were divided into preinvasive group (148 pGGNs) and invasive group (172 pGGNs) according to histopathology. Logistic regression analysis was used to determine the risk factors for invasiveness of pGGN, and the ROC curve analysis was performed on each risk factor.Results:Crescent sign was found in 24 cases (16.2%) in the preinvasive group and 49 (28.5%) in the invasive group, and the difference between the two groups was statistically significant (χ2=6.804 ,P=0.009).There were statistically significant differences in patient′s age, lesion size, shape, lobulation sign, and vascular stretch sign between the two groups ( P<0.05). The ROC curve showed that with the lesion size 10.5 mm as the optimal cut off value, the sensitivity for differential diagnosis of preinvasive and invasive lesions was 65.7%, the specificity was 61.5%, and the area under the curve was 0.666. Logistic regression analysis showed that maximum diameter of the lesion ≥10.5 mm, irregular shape, crescent sign and vascular stretch were independent risk factors of invasiveness of pGGN, and the OR value (95%CI) were 3.192 (1.981-5.144), 3.672 (1.545-8.725), 1.972 (1.104-3.521), and 2.026 (1.087-3.777), respectively. A logistic model was established based on the above four independent risk factors, and the area under curve was 0.711 (95%CI 0.655-0.768). Conclusion:Crescent sign can effectively reflect the invasiveness of pGGN. Maximum diameter of the lesion ≥10.5 mm, irregular shape, crescent sign and vascular stretch sign are independent risk factors of invasiveness of pGGN.

Objective:To investigate the feasibility of tube potential of 80 kV combined with personalized contrast agent protocol in carotid artery CT angiography (CTA).Methods:A total of 136 consecutive patients undergoing neck CTA were prospectively enrolled in this study. The patients were randomly divided into Groups A, B, C and D. Tube potential of 100 kV and 15 s contrast agent injection protocol was used for Group A (53 cases) as conventional group, while tube voltage of 80 kV and 10 s contrast agent injection protocol was used for Groups B, C and D as experimental groups, with the contrast agent dosages of 20, 25 and 30 ml used according to the body weights of ≤50 kg(Group B, 20 cases), 50-70 kg (Group C, 38 cases), and 70-90 kg (Group D, 25 cases), respectively. The subjective and objective evaluation results of image quality and the effective doses were compared among the four groups.Results:The effective doses in Groups B, C and D were 1.54±0.91, 1.89±1.08 and 2.14±1.27 mSv, respectively, significantly lower than that in Group A [(5.66±0.56) mSv] ( F=169.34, P<0.05). The image quality of four groups met the requirements of clinical diagnosis. No significant differences were found in subjective evaluation and diagnostic efficacy of the four groups ( P>0.05). The CT number of carotid artery, signal-to-noise ratio and contrast-to-noise ratio of the neck region were significantly lower in Groups B, C and D compared with Group A ( F=14.9, 12.94, 14.43, P<0.05). The CT numbers of target carotid vessel were all higher than 250 HU. Conclusions:The scanning protocol of low tube potential (80 kV) combined with 10 s contrast agent injection protocol could not only reduce the doses of radiation and contrast agent, but also preserve the diagnosis effect. Thus, this scanning protocol was feasible and valuable in clinical application.

Objective:To explore the feasibility of CT angiography (CTA) in investigating vascular dilatation of anterior choroidal artery (AChA) and posterior communicating artery (PComA) in patients with Moyamoya syndrome (MMS).Methods:From July 2017 to July 2018, the clinical and imaging data of MMS patients with brain CTA and DSA performed were analyzed retrospectively. According to DSA results, 71 MMS patients were divided into unilateral MMS group (20 cases, 20 hemispheres) and bilateral MMS group (51 cases, 102 hemispheres). There were 20 cases in unilateral MMS group, 10 males and 10 females, with an average age of (45±9) years; 51 cases in bilateral MMS group, 24 males and 27 females, with an average age of (44±12) years. The hemispheres were divided into dilated group and non-dilated group according to the dilatation of AChA or PComA. Kappa analysis was used to evaluate the consistency of two inspection methods to judge the expansion of AChA. The lumen diameters of PComA, P1 and P2 segments of posterior cerebral artery were measured on CTA images, and the ratio of PComA/P1 and PComA/P2 were calculated. The repeatability of CTA measures was evaluated by intra-group correlation coefficient. Independent sample t-test was used to compare CTA measurement results between PComA dilated group and non-dilated group, and ROC curve was drawn to calculate the best threshold for diagnosis of PComA expansion. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of CTA measures were calculated. Results:The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of CTA diagnosis of AChA expansion inunilateral MMS were all 100.00%. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of CTA diagnosis of AChA expansionin bilateral MMS were 90.00%, 93.90%, 93.14%, 78.26% and 97.47%. Compared with DSA, there was no significant difference in the diagnostic performance of AChA expansion between single and bilateral MMS diagnosed by CTA ( P>0.05). The two methods had strong consistency (Kappa value was 1.00 and 0.79 respectively, P<0.01). A total of 46 patients (69 cerebral hemispheres) were included in the evaluation of PComA. PComA/P1 (1.09±0.41) and PComA/P2 (0.86±0.13) in the dilated group were significantly higher than those in the non-dilated group (0.71±0.21 for PComA/P1 and 0.75±0.23 for PComA/P2). The differences were statistically significant ( t=-4.59, -2.50, P<0.05). The best threshold in diagnosing PComA expansion was 0.87 (PComA/P1) and 0.76 (PComA/P2), and the sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 84.62%, 83.33%, 84.06%, 86.84%, 80.65% and 79.49%, 60.00%, 71.01%, 72.09% and 69.23%, respectively. Compared with DSA, the Kappa value of CTA measures in diagnosis of PComA expansion was 0.68 (PComA/P1) and 0.40 (PComA/P2), respectively, and the difference was statistically significant ( P<0.05). Conclusions:CTA has a strong consistency with DSA in evaluating the AChA expansion in MMS. When the PComA/P1 ratio on CTA is greater than 0.87, it can be used as the diagnosis criterion for PComA expansion.

Objective To determine clinical features and rupture risk of anterior communicating artery (AComA) aneurysms in different age groups. Methods The clinical data of 519 consecutive patients with AComA aneurysms in the First Affiliated Hospital of Wenzhou Medical University between December 2007 and February 2015 were reviewed and divided into younger group (<65 years) and older group (≥65 years). The clinical characteristics and aneurysm morphologies were compared between the two groups. Results There were 390 aneurysms in younger group, and 129 in older groups. For the younger group, hypertension,the size of the aneurysms, maximum height, perpendicular height, size ratio (SR), aspect ratio (AR), aneurysm angle, A1 segment configuration, morphology showed significantly differences in ruptured aneurysms group compared with those in unruptured aneurysms (P<0.05). The multivariate analysis showed that significant difference between the two groups was aneurysm size ( OR＝1.461,95% CI 1.027-2.079, P＝0.035). For the older group, there were statistically significant differences in hypertension,size of the aneurysms, maximum height, perpendicular height, SR, aneurysm angle, vessel size and the distribution of aneurysm projection between the ruptured aneurysms group and unruptured aneurysms group (P<0.05). The multivariate analysis showed that SR ( OR＝11.516,95% CI 1.782-74.445,P＝0.01) was the only significant predictor of aneurysm rupture. Between the younger and older groups,the distributions of sex, hypertension, smoke, vessel size and SR were statistically significant (P < 0.05). Conclusions For younger people, the males who smoked are more likely to have AcomA aneurysms and the size of the aneurysms is independent risk of aneurysm rupture. For older people, the females with hypertension also more often have AcomA aneurysms and the SR is independently associated with aneurysm rupture.

Objective To assess the influence on radiation dose and image quality of bronchial artery CT angiography for hemoptysis patients with high heart rate and free respiratory with single-cardiac dynamic volumetric scanning using 320-row CT.Methods During October 2016 and May 2017,totally 151 hemoptysis patients with heart rate ≥ 65 bmp and free-breathing were scanned for bronchial artery imaging with prospective ECG-gating 320-detector row dynamic volume CT.The patients were randomly divided into two groups,group A(81 cases) and group B(70 cases).Default multi-cardiac cycle scanning style was used for group A to generate multi-sector images A 1 which were reconstructed corresponding single-sector images A2.Single-cardiac periodic scanning was used to get single-sector images for group B.The effective doses (E) of two scanning types,the quantitative parameters of image quality [vascular CT value,image noise (SD),signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR)] and subjective scoring of group B and A1,A2 were compared.The detection accuracy of the systemic artery-pulmonary circulation shunts was evaluated by ROC curve against digital subtraction angiography (DSA).The measurement data was analyzed by independent sample t test while the grade data was tested by independent sample nonparametric test.Results The median value of radiation dose in group B was significantly lower than that of group A (1.42 mSv vs.3.06 mSv,Z=-8.724,P＜0.05).There were no statistically significant differences in quantitative parameters and subjective scoring points of image quality between group B and group A2 (P＞ 0.05).The median subjective scoring points of group B was 4,which was better than that of group A1 (Z =-10.584,P＜ 0.05).The differences of SD,SNR,CNR betweengroup B and group A1 were statistically significant(t =-0.983,7.898,7.695,P＜0.05),and group B had higher SD,SNR and CNR.There was no significant difference in the mean CT values of the aorta and pulmonary artery between the two groups (P ＞ 0.05).The detection accuracy of the systemic arterypulmonary circulation shunts was moderately high in group B and group A2.The area under the ROC curve (AUC) was 0.891 and 0.864,respectively (Z=7.210,7.430,P＜0.05).The accuracy of group A1 was poor.The area under the ROC curve was 0.626 (Z=2.434,P＜0.05).The sensitivity of group B and groupA2 were 80％ and 76.2％,respectively (P＜0.05),and 28.6％ of group A1 (P＜0.05).Conclusions The 320-row single-cardiac periodic dynamic volume CT can effectively improve the image quality and the detection accuracy of the systemic-pulmonary circulation on CT,and reduce the radiation dose of the bronchial artery CT angiography.

Objective To evaluate the CT features of small lung invasive adenocarcinoma with air?containing space and its relationship with pathological types, and to explore the pathological basis of air?containing space. Methods CT and pathological data of fifty patients with surgically proven lung invasive adenocarcinoma with air?containing space in our hospital from January 2012 to December 2017 were retrospectively reviewed. CT image analysis included image features of tumor and air?containing space. Pathological analysis included pathological subtype, differentiation degree. CT features of tumor and air?containing space were compared with regard to pathological types using chi?square test or Fisher exact text. Analysis of variance was used to compare quantitative data satisfying normal distribution, while those data not satisfying normal distribution were compared with Kruskal?Wallis test. In addition, Spearman correlation was used to analyze the correlation between nodule density and pathological types. Results (1) CT features of tumors: Tumors were predominantly located in peripheral lungs (46/50). Most of the tumors were subsolid nodules (37/50). Tumor?lung interface was generally clear (46/50). Tumors are often accompanied by malignant signs such as lobulation (37/50), spicule sign (27/50), air bronchogram sign (43/50), and pleural indentation (36/50). The mean diameter of nodules ranged from 7.50 mm to 18.12 mm, with an average of (12.91±2.85)mm. The nodule density ranged from-657.00 to 73.00 HU with an average of (-213.88±206.16) HU. (2) CT features of air?containing space:Air?containing spaces were commonly solitary (37/50) and were found to be mainly in an eccentric distribution (29/37). The maximum diameter of air?containing space ranged from 1.00 to 16.00mm, and the average diameter was (4.23±3.14)mm. Air?containing spaces less than 5mm were found in 35 cases (70%), and air?containing spaces more than 5mm were found in 15 cases. (3) Comparison of CT features and corresponding pathological types: Nodule density, number of air?containing space, and type of nodule density in different pathological types were statistically different (P<0.05). There was a correlation between nodule density and pathological subtypes (r=0.371, P=0.008). Differences of nodule density, short?dimension of nodule, type of nodule density, spicule sign, pleural indentation among different tumor differentiation degrees were significant (P<0.05). The degree of tumor differentiation was negatively correlated with nodule density (r=-0.451, P=0.001). Conclusion The detection rate of air?containing space in lung invasive adenocarcinomas is 12.7%. Most small lung invasive adenocarcinomas with air?containing space are presented as peripheral subsolid nodule, and there is a certain correlation between their CT features and pathological types. The pathological basis of air?containing space was supposed to be dilated distal bronchiole induced by check?valve mechanism and destruction of alveolar structure by tumor.

Objective: To evaluate the CT features of small lung invasive adenocarcinoma with air-containing space and its relationship with pathological types, and to explore the pathological basis of air-containing space. Methods: CT and pathological data of fifty patients with surgically proven lung invasive adenocarcinoma with air-containing space in our hospital from January 2012 to December 2017 were retrospectively reviewed. CT image analysis included image features of tumor and air-containing space. Pathological analysis included pathological subtype, differentiation degree. CT features of tumor and air-containing space were compared with regard to pathological types using chi-square test or Fisher exact text. Analysis of variance was used to compare quantitative data satisfying normal distribution, while those data not satisfying normal distribution were compared with Kruskal-Wallis test. In addition, Spearman correlation was used to analyze the correlation between nodule density and pathological types. Results: (1) CT features of tumors: Tumors were predominantly located in peripheral lungs (46/50). Most of the tumors were subsolid nodules (37/50). Tumor-lung interface was generally clear (46/50). Tumors are often accompanied by malignant signs such as lobulation (37/50), spicule sign (27/50), air bronchogram sign (43/50), and pleural indentation (36/50). The mean diameter of nodules ranged from 7.50 mm to 18.12 mm, with an average of (12.91±2.85)mm. The nodule density ranged from-657.00 to 73.00 HU with an average of (-213.88±206.16) HU. (2) CT features of air-containing space: Air-containing spaces were commonly solitary (37/50) and were found to be mainly in an eccentric distribution (29/37). The maximum diameter of air-containing space ranged from 1.00 to 16.00mm, and the average diameter was (4.23±3.14)mm. Air-containing spaces less than 5mm were found in 35 cases (70%), and air-containing spaces more than 5mm were found in 15 cases. (3) Comparison of CT features and corresponding pathological types: Nodule density, number of air-containing space, and type of nodule density in different pathological types were statistically different (P<0.05). There was a correlation between nodule density and pathological subtypes (r=0.371, P=0.008). Differences of nodule density, short-dimension of nodule, type of nodule density, spicule sign, pleural indentation among different tumor differentiation degrees were significant (P<0.05). The degree of tumor differentiation was negatively correlated with nodule density (r=-0.451, P=0.001). Conclusion The detection rate of air-containing space in lung invasive adenocarcinomas is 12.7%. Most small lung invasive adenocarcinomas with air-containing space are presented as peripheral subsolid nodule, and there is a certain correlation between their CT features and pathological types. The pathological basis of air-containing space was supposed to be dilated distal bronchiole induced by check-valve mechanism and destruction of alveolar structure by tumor.

Objective To investigate the clinical application of different puncture positions in percutaneous nephrolithotomy (PCNL).Methods From February 2015 to March 2017,102 patients with kidney urinary calculi in our hospital were enrolled in the study.According to the selected puncture position,they were divided into prone position (group A,32 cases),lateral decubitus position (group B,37 cases) and half stone oblique supine position (group C,33 cases).The mean arterial pressure (MAP),heart rate (HR) and blood oxygen saturation (SpO2) were observed before placement of 5 min (T0),after placement of 5 min (T1),30 min (T2),and postoperative 5 min (T3),and the time of established passage,the time of operation and the amount of bleeding during operation and so on.Results The MAP in group B and group C at T1 was significantly higher than that in group A (P ＜ 0.05);The HR in Group B and group C at T2 and T3 were significantly lower than those in group A (P ＜ 0.05);The SpO2 in Group B and group C at T1 and T2 were significantly higher than those in group A (P ＜ 0.05);There was no significant difference in the time of establishment passage,the rate of primary clearing stone and the hospital stay in the groups (P ＞0.05);The operation time and intraoperative blood loss in group C were (120.07 ± 20.19) min and (90.01 ±30.11)ml,significantly less than those in group B and group A (P ＜0.05);The operation time and intraoperative blood loss in group B were (140.17 ±20.48) min and (110.04 ±29.82) ml,significantly less than that in group A [(170.02 ± 21.02) min,(164.02 ± 30.12) ml] (P ＜ 0.05);The postural comfort of group C was better than that of group A and group B (P ＜ 0.05);There was no significant difference in the incidence of postoperative complications in the three groups (P ＞ 0.05).Conclusions Half stone oblique supine position in the PCNL application has good effect,which is conducive to improving the patient's tolerance to surgery,shorten the operation time,and it is worth popularizing.